What's a chemical compound?
Chemical compound
Chemical compounds have a unique and defined chemical structure held together in a defined spatial arrangement by chemical bonds. Chemical compounds can be molecular compounds held together by covalent bonds, salts held together by ionic bonds, intermetallic compounds held together by metallic bonds, or the subset of chemical complexes that are held together by coordinate covalent bonds. Pure chemical elements are generally not considered chemical compounds, failing the two or more atom requirement, though they often consist of molecules composed of multiple atoms (such as in the diatomic molecule H, or the polyatomic molecule S, etc.). Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service (CAS): its CAS number.
Chemical formula
The law of constant composition says that, in any particular chemical compound, all samples of that compound will be made up of the same elements in the same proportion or ratio. For example, any water molecule is always made up of two hydrogen atoms and one oxygen atom in a 2:1 ratio. If we look at the relative masses of oxygen and hydrogen in a water molecule, we see that 94% of the mass of a water molecule is accounted for by oxygen and the remaining 6% is the mass of hydrogen. This mass proportion will be the same for any water molecule.
Benzene
Benzene is an important organic chemical compound with the chemical formula CH. The benzene molecule is composed of six carbon atoms joined in a ring with one hydrogen atom attached to each. As it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon.
Subject matter in Canadian patent law
“Composition of matter” is defined as a combination of ingredients or substances – a solid, gas, or fluid – as a chemical union or a physical mixture. This definition has been taken to include enzymes, reproducible modified genes, and the cells that carry them. However, "Harvard College v. Canada (Commissioner of Patents)" has drawn a distinction between lower and higher life forms (see below). Where an invention is a combination of elements, the elements must produce something that is more than a mere sum of their individual effects. In other words, if each element functions independently and there is no common result, there is no inventive composition.
Synthesizing unit
Mixtures of the 4 basic modes can occur, especially if the substrates represent generalized compounds, rather than pure chemical compounds. A generalized compound is a mixture of chemical compounds that does not change in composition.
Chemical compound
A compound can be converted to a different chemical composition by interaction with a second chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the interacting compounds, and then bonds are reformed so that new associations are made between atoms.
Chemistry
However, not all substances or chemical compounds consist of discrete molecules, and indeed most of the solid substances that make up the solid crust, mantle, and core of the Earth are chemical compounds without molecules. These other types of substances, such as ionic compounds and network solids, are organized in such a way as to lack the existence of identifiable molecules "per se". Instead, these substances are discussed in terms of formula units or unit cells as the smallest repeating structure within the substance. Examples of such substances are mineral salts (such as table salt), solids like carbon and diamond, metals, and familiar silica and silicate minerals such as quartz and granite.
Solid
One important property of carbon in organic chemistry is that it can form certain compounds, the individual molecules of which are capable of attaching themselves to one another, thereby forming a chain or a network. The process is called polymerization and the chains or networks polymers, while the source compound is a monomer. Two main groups of polymers exist: those artificially manufactured are referred to as industrial polymers or synthetic polymers (plastics) and those naturally occurring as biopolymers.
Organic chemistry
The multiple-step synthesis of complex organic compounds is called total synthesis. Total synthesis of complex natural compounds increased in complexity to glucose and terpineol. For example, cholesterol-related compounds have opened ways to synthesize complex human hormones and their modified derivatives. Since the start of the 20th century, complexity of total syntheses has been increased to include molecules of high complexity such as lysergic acid and vitamin B.
The discovery of petroleum and the development of the petrochemical industry spurred the development of organic chemistry. Converting individual petroleum compounds into different "types" of compounds by various chemical processes led to organic reactions enabling a broad range of industrial and commercial products including, among (many) others: plastics, synthetic rubber, organic adhesives, and various property-modifying petroleum additives and catalysts.
Compounds of carbon
Compounds of carbon are defined as chemical substances containing carbon. More compounds of carbon exist than any other chemical element except for hydrogen. Organic carbon compounds are far more numerous than inorganic carbon compounds. In general bonds of carbon with other elements are covalent bonds. Carbon is tetravalent but carbon free radicals and carbenes occur as short-lived intermediates. Ions of carbon are carbocations and carbanions are also short-lived. An important carbon property is catenation as the ability to form long carbon chains and rings.
Polysulfane
A polysulfane is a chemical compound of formula HS, where x > 1, although sometimes disulfane, HS is excluded. Polysulfanes consist of unbranched chains of sulfur atoms terminated with hydrogen. Compounds containing 2–8 concatenated sulfur atoms have been isolated, longer chain compounds have been detected, but only in solution. HS is colourless, higher members are yellow with the colour increasing with the sulfur content. Even a trace of alkali will cause chemical decomposition, and containers need to be treated with acid to remove any traces of alkali.
In the chemical literature the term polysulfanes is sometimes used for compounds containing −(S)−, e.g. organic polysulfanes R−(S)−R.
Abiogenesis
An organic compound is any member of a large class of gaseous, liquid, or solid chemicals whose molecules contain carbon. Carbon is the fourth most abundant element in the Universe by mass after hydrogen, helium, and oxygen. Carbon is abundant in the Sun, stars, comets, and in the atmospheres of most planets. Organic compounds are relatively common in space, formed by "factories of complex molecular synthesis" which occur in molecular clouds and circumstellar envelopes, and chemically evolve after reactions are initiated mostly by ionizing radiation. Based on computer model studies, the complex organic molecules necessary for life may have formed on dust grains in the protoplanetary disk surrounding the Sun before the formation of the Earth. According to the computer studies, this same process may also occur around other stars that acquire planets.
Biological activity
In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or pharmacophore but can be modified by the other constituents. Among the various properties of chemical compounds, pharmacological/biological activity plays a crucial role since it suggests uses of the compounds in the medical applications. However, chemical compounds may show some adverse and toxic effects which may prevent their use in medical practice.
Combination reaction
A combination reaction (also known as a synthesis reaction) is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product). Such reactions may be represented by equations of the following form: X + Y → XY.
The combination of two or more elements and form one compound is called combination reaction. 
Combination reactions can involve different types of reactants:
There is no specific number of reactants in a combination reaction.
Quaternary compound
In chemistry, a quaternary compound is a cation consisting of a central positively charged atom with four substituents, especially organic (alkyl and aryl) groups, discounting hydrogen atoms.
Chemical substance
Compounds in which components share electrons are known as covalent compounds. Compounds consisting of oppositely charged ions are known as ionic compounds, or salts.
Chemistry
According to the IUPAC gold book, a chemical reaction is "a process that results in the interconversion of chemical species." Accordingly, a chemical reaction may be an elementary reaction or a stepwise reaction. An additional caveat is made, in that this definition includes cases where the interconversion of conformers is experimentally observable. Such detectable chemical reactions normally involve sets of molecular entities as indicated by this definition, but it is often conceptually convenient to use the term also for changes involving single molecular entities (i.e. 'microscopic chemical events').
Organic compound
Compounds that are prepared by reaction of other compounds are known as "synthetic". They may be either compounds that already are found in plants or animals or those that do not occur naturally.
Organic chemistry
Organic chemistry is the chemistry subdiscipline for the scientific study of structure, properties, and reactions of organic compounds and organic materials (materials that contain carbon atoms). Study of structure determines their chemical composition and formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study.
Chemical compound microarray
A chemical compound microarray is a collection of organic chemical compounds spotted on a solid surface, such as glass and plastic. This microarray format is very similar to DNA microarray, protein microarray and antibody microarray. In chemical genetics research, they are routinely used for searching proteins that bind with specific chemical compounds, and in general drug discovery research, they provide a multiplex way to search potential drugs for therapeutic targets.
Organozirconium chemistry
Organozirconium compounds are organometallic compounds containing a carbon to zirconium chemical bond. Organozirconium chemistry is the corresponding science exploring properties, structure and reactivity of these compounds. In general organozirconium compounds are stable and non-toxic. They are used in organic chemistry as an intermediate in the synthesis of chemical compounds and share characteristics with organotitanium compounds also a Group 4 element. Organozirconium compounds have been widely studied, in part because they are useful catalysts in Ziegler-Natta polymerization.
English compound
These types account for most compound nouns, but there are other, rarer types as well. "Coordinative", "copulative" or "dvandva" compounds combine elements with a similar meaning, and the compound meaning may be a generalization instead of a specialization. "Bosnia-Herzegovina", for example, is the combined area of Bosnia and Herzegovina, but a "fighter-bomber" is an aircraft that is both a fighter and a bomber. "Iterative" or "amredita" compounds repeat a single element, to express repetition or as an emphasis. "Day by day" and "go-go" are examples of this type of compound, which has more than one head.
Bridged compounds
Bridged compounds may be fully carbocyclic (all carbon) or heterocyclic (having one or more non-carbon atoms). The principal and bridging rings are almost always different in nature, though they can be identical. Although sketches of organic structures may make bridged compounds appear planar, they are not; for instance, comparing the 3D ball-and-stick model of norbornane at left, with the image shown at right, makes clear the bridging ring ensures that the molecule is not planar.
Chemical compound
A compound can be converted to a different chemical composition by interaction with a second chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the interacting compounds, and then bonds are reformed so that new associations are made between atoms. Schematically, this reaction could be described as , where A, B, C, and D are each unique atoms; and AB, AD, CD, and CB are each unique compounds.
Open-chain compound
In chemistry, an open-chain compound (also spelled as open chain compound) or acyclic compound (Greek prefix "α", "without" and "κύκλος", "cycle") is a compound with a linear structure, rather than a cyclic one.
An open-chain compound having no side chains is called a straight-chain compound (also spelled as straight chain compound). Many of the simple molecules of organic chemistry, such as the alkanes and alkenes, have both linear and ring isomers, that is, both acyclic and cyclic, with the latter often classified as aromatic. For those with 4 or more carbons, the linear forms can have straight-chain or branched-chain isomers. The lowercase prefix "n-" denotes the straight-chain isomer; for example, "n"-butane is straight-chain butane, whereas "i"-butane is isobutane. Cycloalkanes are isomers of alkenes, not of alkanes, because the ring's closure involves a C=C bond. Having no rings (aromatic or otherwise), all open-chain compounds are aliphatic.
Chemical substance
In organic chemistry, there can be more than one chemical compound with the same composition and molecular weight. Generally, these are called isomers. Isomers usually have substantially different chemical properties, and often may be isolated without spontaneously interconverting. A common example is glucose vs. fructose. The former is an aldehyde, the latter is a ketone. Their interconversion requires either enzymatic or acid-base catalysis.
Phenols
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group (—OH) bonded directly to an aromatic hydrocarbon group. The simplest of the class is phenol, . Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule.
Butene
Among the molecules which have the chemical formula four isomers are alkenes. All four of these hydrocarbons have four carbon atoms and one double bond in their molecules, but have different chemical structures. The IUPAC and common names, respectively, of these chemical compounds are:
In the chemical structures above, the small blue numbers in the structure images are the numbering of the atoms in the main backbone chain of the molecules. Other organic compounds have the formula CH, namely cyclobutane and methylcyclopropane, but are not alkenes and do not fall under the name "butene". There are also cyclic alkenes with four carbon atoms overall such as cyclobutene and two isomers of methylcyclopropene, but they do not have the formula CH and are not discussed here.
Drug Quality and Security Act
Compounding is the creation of a particular pharmaceutical product to fit the unique need of a patient. To do this, compounding pharmacists combine or process appropriate ingredients using various tools. This may be done for medically necessary reasons, such as to change the form of the medication from a solid tablet to a liquid, to avoid a non-essential ingredient that the patient is allergic to, or to obtain the exact dose(s) needed or deemed best of particular active pharmaceutical ingredient(s). It may also be done for more optional reasons, such as adding flavors to a medication or otherwise altering taste or texture.
List of chemical compounds with unusual names
Chemical nomenclature, replete as it is with compounds with complex names, is a repository for some very peculiar and sometimes startling names. A browse through the "Physical Constants of Organic Compounds" in the "CRC Handbook of Chemistry and Physics" (a fundamental resource) will reveal not just the whimsical work of chemists, but the sometimes peculiar compound names that occur as the consequence of simple juxtaposition. Some names derive legitimately from their chemical makeup, from the geographic region where they may be found, the plant or animal species from which they are isolated or the name of the discoverer.
Organic compound
In chemistry, an organic compound is generally any chemical compound that contains carbon. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Study of the properties and synthesis of organic compounds is the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonates and cyanides), along with a handful of other exceptions (e.g., carbon dioxide), are not classified as organic compounds and are considered inorganic. No consensus exists among chemists on precisely which carbon-containing compounds are excluded, making the definition of an organic compound elusive. Although organic compounds make up only a small percentage of the Earth's crust, they are of central importance because all known life is based on organic compounds. Most synthetically produced organic compounds are ultimately derived from petrochemicals consisting mainly of hydrocarbons.
Aroma compound
An aroma compound, also known as an odorant, aroma, fragrance, or flavor, is a chemical compound that has a smell or odor. A chemical compound has a smell or odor when it is sufficiently volatile to be transported to the olfactory system in the upper part of the nose.
Xenon
After Neil Bartlett's discovery in 1962 that xenon can form chemical compounds, a large number of xenon compounds have been discovered and described. Almost all known xenon compounds contain the electronegative atoms fluorine or oxygen. The chemistry of xenon in each oxidation state is analogous to that of the neighboring element iodine in the immediately lower oxidation state.
Chemical bond
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force and hydrogen bonding.
Chemical state
The chemical state of a chemical element is due to its electronic, chemical and physical properties as it exists in combination with itself or a group of one or more other elements. A chemical state is often defined as an "oxidation state" when referring to metal cations. When referring to organic materials, a chemical state is usually defined as a chemical group, which is a group of several elements bonded together. Material scientists, solid state physicists, analytical chemists, surface scientists and spectroscopists describe or characterize the chemical, physical and/or electronic nature of the surface or the bulk regions of a material as having or existing as one or more chemical states.
Joint compound
Joint compound (also known as drywall compound or Mastic) is a white powder of primarily gypsum dust mixed with water to form a mud the consistency of cake frosting, which is used with paper or fiber "joint tape" to seal joints between sheets of drywall to create a seamless base for paint on interior walls. It is often referred to simply as mud or as joint cement
Chemical Weapons Convention
The treaty also deals with carbon compounds called in the treaty "discrete organic chemicals", the majority of which exhibit moderate-high direct toxicity or can be readily converted into compounds with toxicity sufficient for practical use as a chemical weapon. These are any carbon compounds apart from long chain polymers, oxides, sulfides and metal carbonates, such as organophosphates. The OPCW must be informed of, and can inspect, any plant producing (or expecting to produce) more than 200 tonnes per year, or 30 tonnes if the chemical contains phosphorus, sulfur or fluorine, unless the plant solely produces explosives or hydrocarbons.
Inorganic compound
An inorganic compound is typically a chemical compound that lacks C-H bonds, that is, a compound that is not an organic compound, but the distinction is not defined or even of particular interest.
Lead compound
A lead compound may arise from a variety of different sources. Lead compounds are found by characterizing natural products, employing combinatorial chemistry, or by molecular modeling as in rational drug design. Chemicals identified as hits through high-throughput screening may also become lead compounds. Once a lead compound is selected it must undergo lead optimization, which involves making the compound more "drug-like." This is where Lipinski's rule of five comes into play, sometimes also referred to as the "Pfizer rule" or simply as the "rule of five." Other factors, such as the ease of scaling up the manufacturing of the chemical, must be taken into consideration.
Aliphatic compound
In organic chemistry, hydrocarbons (compounds composed of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. "aleiphar", fat, oil), also known as non-aromatic compounds. Aliphatics can be cyclic, but only aromatic compounds contain an especially stable ring of atoms, such as benzene. Aliphatic compounds can be saturated, like hexane, or unsaturated, like hexene and hexyne. Open-chain compounds (whether straight or branched) contain no rings of any type, and are thus aliphatic.
Chemistry
A "molecule" is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances. However, this definition only works well for substances that are composed of molecules, which is not true of many substances (see below). Molecules are typically a set of atoms bound together by covalent bonds, such that the structure is electrically neutral and all valence electrons are paired with other electrons either in bonds or in lone pairs.
Organolead compound
Organolead compounds are chemical compounds containing a chemical bond between carbon and lead. Organolead chemistry is the corresponding science. The first organolead compound was hexaethyldilead (Pb(CH)), first synthesized in 1858. Sharing the same group with carbon, lead is tetravalent.
Chlordane
Chlordane is a chemical compound and also part of a similarly named pesticide mixture resulting from synthesis (main components- heptachlor, chlordane, and nonachlor). These highly chlorinated cyclodienes were classified as organic pollutants hazardous for human health. They are both resistant to degradation in the environment and in humans/animals and readily accumulate in lipids (fats) of human/animals. Exposure to these compounds has been linked to cancers and many other diseases.
Heterocyclic compound
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles.
Chemical affinity
In chemical physics and physical chemistry, chemical affinity is the electronic property by which dissimilar chemical species are capable of forming chemical compounds. Chemical affinity can also refer to the tendency of an atom or compound to combine by chemical reaction with atoms or compounds of unlike composition.
Molecule
A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with oxygen (O); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (HO). Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not considered single molecules.
Organic compound
The relatively narrow definition of organic compounds as those containing C-H bonds excludes compounds that are (historically and practically) considered organic. Neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid. Other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered a possible organic substance in Martian soil. Terrestrially, it, and its anhydride, mellitic anhydride, are associated with the mineral mellite (AlC(COO)·16HO).
Organic compound
As described in detail below, any definition of organic compound that uses simple, broadly applicable criteria turns out to be unsatisfactory, to varying degrees. The modern, commonly accepted definition of organic compound essentially amounts to any carbon containing compound, excluding several classes of substances traditionally considered as 'inorganic'. However, the list of substances so excluded varies from author to author. Still, it is generally agreed upon that there are (at least) a few carbon containing compounds that should not be considered organic. For instance, almost all authorities would require the exclusion of alloys that contain carbon, including steel (which contains cementite, FeC), as well as other metal and semimetal carbides (including "ionic" carbides, e.g, AlC and CaC and "covalent" carbides, e.g. BC and SiC, and graphite intercalation compounds, e.g. KC). Other compounds and materials that are considered 'inorganic' by most authorities include: metal carbonates, simple oxides (CO, CO, and arguably, CO), the allotropes of carbon, cyanide derivatives not containing an organic residue (e.g., KCN, (CN), BrCN, CNO, etc.), and heavier analogs thereof (e.g., CP 'cyaphide anion', CSe, COS; although CS 'carbon disulfide' is often classed as an "organic" solvent). Halides of carbon without hydrogen (e.g., CF and CClF), phosgene (COCl), carboranes, metal carbonyls (e.g., nickel carbonyl), mellitic anhydride (CO), and other exotic oxocarbons are also considered inorganic by some authorities.
Compound (linguistics)
In linguistics, a compound is a lexeme (less precisely, a word) that consists of more than one stem. Compounding, composition or nominal composition is the process of word formation that creates compound lexemes. That is, in familiar terms, compounding occurs when two or more words are joined to make one longer word. The meaning of the compound may be similar to or different from the meaning of its components in isolation. The component stems of a compound may be of the same part of speech—as in the case of the English word "footpath", composed of the two nouns "foot" and "path"—or they may belong to different parts of speech, as in the case of the English word "blackbird", composed of the adjective "black" and the noun "bird". With very few exceptions, English compound words are stressed on their first component stem.
Homoleptic
In inorganic chemistry, a homoleptic chemical compound is a metal compound with all ligands identical. The term uses the "homo-" prefix to indicate that something is the same for all.
Chemical substance
All matter consists of various elements and chemical compounds, but these are often intimately mixed together. Mixtures contain more than one chemical substance, and they do not have a fixed composition. In principle, they can be separated into the component substances by purely mechanical processes. Butter, soil and wood are common examples of mixtures.
Chemical clock
A chemical clock (or clock reaction) is a complex mixture of reacting chemical compounds in which the onset of an observable property occurs after a predictable induction time. 
In cases where one of the reagents has a visible color, crossing a concentration threshold can lead to an abrupt color change after a reproducible time lapse.
Chemical substance
Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride) and refined sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical.
Chemical substance
Many compounds are also known by their more common, simpler names, many of which predate the systematic name. For example, the long-known sugar glucose is now systematically named 6-(hydroxymethyl)oxane-2,3,4,5-tetrol. Natural products and pharmaceuticals are also given simpler names, for example the mild pain-killer Naproxen is the more common name for the chemical compound (S)-6-methoxy-α-methyl-2-naphthaleneacetic acid.
Inorganic compound
Inorganic compounds can be defined as any compound that is not organic compound. Some simple compounds that contain carbon are often considered inorganic. Examples include carbon monoxide, carbon dioxide, carbonates, cyanides, cyanates, carbides, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms, which means that describing a chemical as inorganic does not obligately mean that it does not occur within living things.
Chemical affinity
In chemical physics and physical chemistry, chemical affinity is the electronic property by which dissimilar chemical species are capable of forming chemical compounds. Chemical affinity can also refer to the tendency of an atom or compound to combine by chemical reaction with atoms or compounds of unlike composition.
Dipolar compound
In organic chemistry, a dipolar compound or simply dipole is an electrically neutral molecule carrying a positive and a negative charge in at least one canonical description. In most dipolar compounds the charges are delocalized.
Unlike salts, dipolar compounds have charges on separate atoms, not on positive and negative ions that make up the compound. Dipolar compounds exhibit a dipole moment.
Saturated and unsaturated compounds
In organic chemistry, a saturated compound is a chemical compound that has single bonds.
Composition of matter
A composition of matter is an instrument formed by the intermixture of two or more ingredients, and possessing properties which belong to none of these ingredients in their separate state. ...The intermixture of ingredients in a composition of matter may be produced by mechanical or chemical operations, and its result may be a compound substance resolvable into its constituent elements by mechanical processes, or a new substance which can be destroyed only by chemical analysis.
Non-stoichiometric compound
Non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by integers; most often, in such materials, some small percentage of atoms are missing or too many atoms are packed into an otherwise perfect lattice work. Contrary to earlier definitions, modern understanding of non-stoichiometric compounds view them as homogenous, and not mixtures of stoichiometric chemical compounds. Since the solids are overall electrically neutral, the defect is compensated by a change in the charge of other atoms in the solid, either by changing their oxidation state, or by replacing them with atoms of different elements with a different charge. Many metal oxides and sulfides have non-stoichiometric examples; for example, stoichiometric iron(II) oxide, which is rare, has the formula FeO, whereas the more common material is nonstoichiometric, with the formula FeO. The type of equilibrium defects in non-stoichiometric compounds can vary with attendant variation in bulk properties of the material. Non-stoichiometric compounds also exhibit special electrical or chemical properties because of the defects; for example, when atoms are missing, electrons can move through the solid more rapidly. Non-stoichiometric compounds have applications in ceramic and superconductive material and in electrochemical (i.e., battery) system designs.
List of benzo compounds
Benzo might also refer to: Benzodiazepine 
In organic chemistry the addition of the prefix benzo to the name of a chemical compound indicates the addition of an even number of carbon atoms to an unsaturated or already aromatic compound by which a new aromatic ring is formed. Between the prefix "benzo" and the name of the parent compound then place of the addition of the extra carbon atoms is indicated by letters written between square brackets. Quite often the number of added carbon atoms is four, although sometimes two else will do the job as shown in the following table. The first entry also shows different routes to the name of the same molecule.
Solid solution
A solid solution is a solid-state solution of one or more solutes in a solvent. Such a multi-component system is considered a solution rather than a compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the chemical components remain in a single homogeneous phase. This often happens when the two elements (generally metals) involved are close together on the periodic table; conversely, a chemical compound generally results when two metals involved are not near each other on the periodic table.
C3H4O
CHO is a chemical formula that represents each of several actual and hypothetical compounds that differ in structure, but each consist of three atoms of carbon, four of hydrogen, and one of oxygen. The following compounds are among them:The following additional such compounds are discussed in an order that facilitates reference to the accompanying structural graphic:
Oxocarbon
An oxocarbon or oxide of carbon is a chemical compound consisting only of carbon and oxygen.
Chemical composition
The chemical composition of a pure substance corresponds to the relative amounts of the elements that constitute the substance itself. It can be expressed with a chemical formula, such as an empirical or molecular formula.
Hydrogen
Hydrogen forms a vast array of compounds with carbon called the hydrocarbons, and an even vaster array with heteroatoms that, because of their general association with living things, are called organic compounds. The study of their properties is known as organic chemistry and their study in the context of living organisms is known as biochemistry. By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond which gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated synthetic pathways that seldom involve elemental hydrogen.
Selenium dioxide
Selenium dioxide is the chemical compound with the formula SeO. This colorless solid is one of the most frequently encountered compounds of selenium.
Chemical composition
Chemical composition refers to the identity and relative number of the chemical elements that make up any particular compound.
Chemical compound
A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using the standard abbreviations for the chemical elements, and subscripts to indicate the number of atoms involved. For example, water is composed of two hydrogen atoms bonded to one oxygen atom: the chemical formula is HO. Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service (CAS): its CAS number.
Organic compound
Even though vitalism has been discredited, scientific nomenclature retains the distinction between "organic" and "inorganic" compounds. The modern meaning of "organic compound" is any compound that contains a significant amount of carbon—even though many of the organic compounds known today have no connection to any substance found in living organisms. The term "carbogenic" has been proposed by E. J. Corey as a modern alternative to "organic", but this neologism remains relatively obscure.
Chemical formula
A condensed chemical formula may represent the types and spatial arrangement of bonds in a simple chemical substance, though it does not necessarily specify isomers or complex structures. For example, ethane consists of two carbon atoms single-bonded to each other, with each carbon atom having three hydrogen atoms bonded to it. Its chemical formula can be rendered as CHCH. In ethylene there is a double bond between the carbon atoms (and thus each carbon only has two hydrogens), therefore the chemical formula may be written: CHCH, and the fact that there is a double bond between the carbons is implicit because carbon has a valence of four. However, a more explicit method is to write HC=CH or less commonly HC::CH. The two lines (or two pairs of dots) indicate that a double bond connects the atoms on either side of them.
Organometallic chemistry
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkaline, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and tin, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal phosphine complexes are representative members of this class. The field of organometallic chemistry combines aspects of traditional inorganic and organic chemistry.
Compounds of carbon
It was once thought that organic compounds could only be created by living organisms. Over time, however, scientists learned how to synthesize organic compounds in the lab. The number of organic compounds is immense and the known number of defined compounds is close to 10 million. However, an indefinitely large number of such compounds are theoretically possible. 
By definition, an organic compound must contain at least one atom of carbon, but this criterion is not generally regarded as sufficient. Indeed, the distinction between organic and inorganic compounds is ultimately a matter of convention, and there are several compounds that have been classified either way, such as:
COCl,
CSCl,
CS(NH),
CO(NH).
With carbon bonded to metals the field of organic chemistry crosses over into organometallic chemistry.
Chemical messenger
A chemical messenger is any compound that serves to transmit a message.
Silica (disambiguation)
Silica or silicon dioxide is a chemical compound.
Chemical composition
The chemical composition of a mixture can be defined as the distribution of the individual substances that constitute the mixture, called "components". In other words, it is equivalent to quantifying the concentration of each component. Because there are different ways to define the concentration of a component, there are also different ways to define the composition of a mixture. It may be expressed as molar fraction, volume fraction, mass fraction, molality, molarity or normality or mixing ratio.
Chemical formula
A chemical formula used for a series of compounds that differ from each other by a constant unit is called a "general formula". It generates a homologous series of chemical formulas. For example, alcohols may be represented by the formula CHOH ("n" ≥ 1), giving the homologs methanol, ethanol, propanol for "n"=1–3.
Sandwich compound
In organometallic chemistry, a sandwich compound is a chemical compound featuring a metal bound by haptic covalent bonds to two arene ligands. The arenes have the formula CH, substituted derivatives (for example C(CH)) and heterocyclic derivatives (for example BCH). Because the metal is usually situated between the two rings, it is said to be "sandwiched". A special class of sandwich complexes are the metallocenes.
Methoxyflurane
The carbon–fluorine bond, a component of all organofluorine compounds, is the strongest chemical bond in organic chemistry. Furthermore, this bond becomes shorter and stronger as more fluorine atoms are added to the same carbon on a given molecule. Because of this, fluoroalkanes are some of the most chemically stable organic compounds.
Chemical substance
A chemical substance may well be defined as "any material with a definite chemical composition" in an introductory general chemistry textbook. According to this definition a chemical substance can either be a pure chemical element or a pure chemical compound. But, there are exceptions to this definition; a pure substance can also be defined as a form of matter that has both definite composition and distinct properties. The chemical substance index published by CAS also includes several alloys of uncertain composition. Non-stoichiometric compounds are a special case (in inorganic chemistry) that violates the law of constant composition, and for them, it is sometimes difficult to draw the line between a mixture and a compound, as in the case of palladium hydride. Broader definitions of chemicals or chemical substances can be found, for example: "the term 'chemical substance' means any organic or inorganic substance of a particular molecular identity, including – (i) any combination of such substances occurring in whole or in part as a result of a chemical reaction or occurring in nature".
Inclusion compound
In host–guest chemistry, an inclusion compound is a complex in which one chemical compound (the "host") has a cavity into which "guest" compound can be accommodated. The interaction between the host and guest involves purely van der Waals bonding. The definition of inclusion compounds is very broad, extending to channels formed between molecules in a crystal lattice in which guest molecules can fit. 
Calixarenes and related formaldehyde-arene condensates are one class of hosts that form inclusion compounds. One famous illustration is the adduct with cyclobutadiene, which otherwise is unstable.
Saturated and unsaturated compounds
Saturated compounds are generally more stable and less reactive than unsaturated compounds since no steric hindrances and no major polarity differences occur. In addition, they have very low melting and boiling points relative to their molar mass.
Unsaturated compounds are organic-chemical compounds whose molecular structure contains one or more carbon-carbon double bonds or triple bonds. These can also be conjugated. Examples are the unsaturated fatty acids or unsaturated hydrocarbons (alkenes and alkynes). Many natural products are unsaturated compounds.
Chemical substance
In law, "chemical substances" may include both pure substances and mixtures with a defined composition or manufacturing process. For example, the EU regulation REACH defines "monoconstituent substances", "multiconstituent substances" and "substances of unknown or variable composition". The latter two consist of multiple chemical substances; however, their identity can be established either by direct chemical analysis or reference to a single manufacturing process. For example, charcoal is an extremely complex, partially polymeric mixture that can be defined by its manufacturing process. Therefore, although the exact chemical identity is unknown, identification can be made to a sufficient accuracy. The CAS index also includes mixtures.
Morphan
Morphan is a chemical compound.
Solid
Organic chemistry studies the structure, properties, composition, reactions, and preparation by synthesis (or other means) of chemical compounds of carbon and hydrogen, which may contain any number of other elements such as nitrogen, oxygen and the halogens: fluorine, chlorine, bromine and iodine. Some organic compounds may also contain the elements phosphorus or sulfur. Examples of organic solids include wood, paraffin wax, naphthalene and a wide variety of polymers and plastics.
Cyanogen (disambiguation)
Cyanogen is a chemical compound.
Hydrocarbon mixtures
A hydrocarbon is any chemical compound that consists only of the elements carbon (C) and hydrogen (H). They all contain a carbon frame, and have hydrogen atoms attached to the frame. Often the term is used as a shortened form of the term aliphatic hydrocarbon. Most hydrocarbons are combustible.
Cyclic compound
A cyclic compound ("ring compound") is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon (i.e., are carbocycles), none of the atoms are carbon (inorganic cyclic compounds), or where both carbon and non-carbon atoms are present (heterocyclic compounds). Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic, in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size (e.g., <17 total atoms) numbers in the many billions.
Mixture
In chemistry, a mixture is a material made up of two or more different substances which are mixed. A mixture refers to the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.
International Cyanide Management Code
Cyanide is a general term for a group of chemicals containing carbon and nitrogen. Cyanide compounds include both naturally occurring and human-made chemicals.
Molecule
A compound's empirical formula is a very simple type of chemical formula. It is the simplest integer ratio of the chemical elements that constitute it. For example, water is always composed of a 2:1 ratio of hydrogen to oxygen atoms, and ethyl alcohol or ethanol is always composed of carbon, hydrogen, and oxygen in a 2:6:1 ratio. However, this does not determine the kind of molecule uniquely – dimethyl ether has the same ratios as ethanol, for instance. Molecules with the same atoms in different arrangements are called isomers. Also carbohydrates, for example, have the same ratio (carbon:hydrogen:oxygen= 1:2:1) (and thus the same empirical formula) but different total numbers of atoms in the molecule.
Alicyclic compound
An alicyclic compound is an organic compound that is both aliphatic and cyclic. They contain one or more all-carbon rings which may be either saturated or unsaturated, but do not have aromatic character. Alicyclic compounds may have one or more aliphatic side chains attached.
Chemical substance
Chemical substances exist as solids, liquids, gases, or plasma, and may change between these phases of matter with changes in temperature or pressure. Chemical substances may be combined or converted to others by means of chemical reactions.
Composite material
A composite material (also called a composition material or shortened to composite, which is the common name) is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure, differentiating composites from mixtures and solid solutions.
Chemical library
A chemical library or compound library is a collection of stored chemicals usually used ultimately in high-throughput screening or industrial manufacture. The chemical library can consist in simple terms of a series of stored chemicals. Each chemical has associated information stored in some kind of database with information such as the chemical structure, purity, quantity, and physiochemical characteristics of the compound.
Azaspirodecane
Azaspirodecane is a chemical compound.
Oxohalide
Molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula AOX, X = F, Cl, Br, I. The element A may be a main group element, a transition element or an actinide. The term oxohalide, or oxyhalide, may also refer to minerals and other crystalline substances with the same overall chemical formula, but having an ionic structure.
Ureas
In chemistry, ureas are a class of organic compounds with the formula (RN)CO where R = H, alkyl, aryl, etc. Thus, in addition to describing a specific chemical compound (HN)CO), urea is the name of a functional group that is found in many compounds and materials of both practical and theoretical interest. Generally ureas are colorless crystalline solids, which, owing to the presence of fewer hydrogen bonds, exhibit melting points lower than that of urea itself.
Composition of matter
The United States Supreme Court has defined "composition of matter" to mean "all compositions of two or more substances and all composite articles, whether they be the results of chemical union, or of mechanical mixture, or whether they be gases, fluids, powders or solids." That definition is problematic, however, because composite articles can be articles of manufacture—as in the case of a piece of plywood, a concrete sidewalk, a road, a fibreglass bathtub, a (kitchen) countertop, or a flitch beam.
Chemical chaperone
Chemical compounds that have varying degrees of hydrophobicity that still are soluble in aqueous environments can act as chemical chaperones as well. These compounds are thought to act by binding to solvent-exposed hydrophobic segments of unfolded or improperly folded proteins, thereby “protecting” them from aggregation. 4-phenylbutyrate (PBA) is a prominent example of this group of compounds, along with lysophosphatidic acids and other lipids and detergents.
Chemical substance
A chemical compound can be either atoms bonded together in molecules or crystals in which atoms, molecules or ions form a crystalline lattice. Compounds based primarily on carbon and hydrogen atoms are called organic compounds, and all others are called inorganic compounds. Compounds containing bonds between carbon and a metal are called organometallic compounds.