What is Benzene?
[[File:Benzene-aromatic-3D-balls.png|thumb|Model of a molecule of benzene. [[Carbon]] atoms are shown as black and [[hydrogen]] as white.]] [[File:Stamps of Germany (BRD) 1964, MiNr 440.jpg|thumb|In 1964, the German postal service issued a [[stamp]] in commemoration of 100 years discovery of Benzene]] '''Benzene''', also known as '''benzol''', is an [[organic compound|organic chemical compound]] with the formula [[Carbon|C]]<sub>6</sub>[[Hydrogen|H]]<sub>6</sub>. It is a [[color]]less and [[flammable]] [[liquid]] with a sweet smell. Benzene molecules are a ring of six carbon atoms that are each [[chemical bond|bonded]] to one [[hydrogen atom]]. It is an ''aromatic'' compound, meaning the ring has alternating double bonds. Benzene is [[carcinogen]]ic, which means it can cause [[cancer]]. It has many real-world uses. It is used as an additive in [[gasoline]], [[plastic]]s, synthetic [[rubber]], [[dye]]s and it is an industrial [[solvent]], which means it can dissolve many other chemical molecules. Benzene is also a natural part of [[Petroleum|crude oil]] and is therefore present in [[gasoline]]. Many [[medicine]]s contain parts made from benzene. ==Structure== Benzene has special properties called [[aromaticity]]. All six carbon atoms in the ring are on the same flat [[Plane (mathematics)|plane]]. To account for all the bonds on a six carbon ring, there must be alternating [[double bond|double]] carbon bonds ([[Conjugated system]]):<ref>[http://www.chemguide.co.uk/basicorg/bonding/benzene1.html bonding in benzene – the Kekulé structure]</ref> [[File:Benzene Representations.svg|thumb|center|639x639px|The various representations of benzene]] If benzene had three double bonds, three sides of its ring would be shorter than the other three sides. [[X-ray diffraction]] shows that all of six carbon-carbon bonds in benzene are of the same length of 140 [[picometre]]s (pm). The C–C [[bond length]]s are greater than a double bond (135 pm) but shorter than a single bond (147 pm).<!--147pm is the sp2–sp2 single bond leng