Structural formula

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Structural formula is a chemical formula which demonstrates the atomic composition and the arrangement of atoms with respect to the bonds formed between them. At times individual atoms and bonds are ommitted and a molecular formula is used instead. The common, two dimensional notation, provides information on the three dimensional arrangment of atoms but does not indicate this directly. For example, you must know about sp3 hybridization in order to deduce the tetrahedral structure of methane, as this is not indicated by it's commonly drawn structural formula. 

However, it is possible to turn a two dimensional structural formula into a three dimensional structural formula with the use of conventional symbols for three dimensional bond arrangement. A thick line indicates a bond in the plane of the paper, a dotted line indicates a bond with outwards direction (that is distanced away from the spectator) and a filled triangle indicates a bond closest to the spectator. (Please visit the reference for clear illustrations, as I am unable to insert them here for an unknown reason)

Of course, these are not ultimately accurate in describing the three dimensional structure of a molecule. For this purpose space-filling models, wire models, computer rendering and other representations are used[1]


  1. J Clark. How to draw organic molecules. Nov 2012. Cited: 04.12.2016 12:53. Available from:

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