What is Aldehyde?
[[Image:Aldehyd - Aldehyde.svg|thumb|150px|right|An aldehyde.]] [[File:Formaldehyde-2D.svg|thumb|upright=0.7|[[Formaldehyde]], which is the simplest aldehyde]] An '''aldehyde''' ({{IPAc-en|ˈ|æ|l|d|ᵻ|h|aɪ|d}}) is an [[organic compound]]. It contains a [[formaldehyde|formyl]] group. A formyl group is a part of a [[molecule]] with the structure R-CHO. It is made of a carbon double bonded to oxygen. The carbon is also bonded to [[hydrogen]] and an [[side chain|R group]].<ref>IUPAC Gold Book [http://goldbook.iupac.org/A00208.html aldehydes]</ref> A side chain is the rest of the molecule. The group without the side chain is called the '''aldehyde group''' or '''formyl group'''. Aldehydes are different from [[ketone]]s because the formyl group is at the end of the molecule in an aldehyde. Ketones have the formyl group in the middle of the molecule. Aldehydes are common in [[organic chemistry]]. Many [[fragrance]]s (smell producing compounds) are aldehydes. <!-- std fxnl group org: Nomenclature Structure and bonding Physical properties and characterization Applications and occurrence Preparation Reactions--> ==Structure and bonding== Aldehydes have a carbon double bonded to an oxygen. Because of this, they are slightly [[polar]]. This causes aldehydes to have a number of properties. One of the most important of these is [[solubility]] in water. ==Nomenclature== ===IUPAC names for aldehydes=== The common names for aldehydes are not always the official names. The [[IUPAC]] names are useful, however. IUPAC recommends the following nomenclature for aldehydes:<ref>[http://www.uwc.edu/dept/chemistry/helpful_files/nomenclature.pdf Short Summary of IUPAC Nomenclature of Organic Compounds], web page, University of Wisconsin Colleges, accessed on line August 4, 2007.</ref><ref>[http://www.acdlabs.com/iupac/nomenclature/93/r93_449.htm §R-5.6.1, Aldehydes, thioaldehydes, and their analogues, A Guide to IUPAC Nomenclature of Organic Compounds: recommendations 1993], IUPAC, Commission on Nomenclature of Organic Chemistry,