Editing Structural formula (section)

== Condensed formulas ==

In early organic-chemistry publications, where use of graphics was strongly limited, a typographic system arose to describe organic structures in a line of text. Although this system tends to be problematic in application to cyclic compounds, it remains a convenient way to represent simple structures:

:{{chem2 | CH3CH2OH }} ([[ethanol]])

Parentheses are used to indicate multiple identical groups, indicating attachment to the nearest non-hydrogen atom on the left when appearing within a formula, or to the atom on the right when appearing at the start of a formula:

:{{chem2 | (CH3)2CHOH or CH(CH3)2OH }} ([[isopropanol|2-propanol]])

In all cases, all atoms are shown, including hydrogen atoms. It is also helpful to show the carbonyls where the C=O is implied through the O being placed in the parentheses.  For example:

:{{chem2 | CH3C(O)CH3 }} ([[acetone]])

Therefore, it is important to look to the left of the atom in the parentheses to make sure what atom it is attached to. This is helpful when converting from condensed formula to another form of structural formula such as [[skeletal formula]] or [[Lewis structure]]s. There are different ways to show the various [[functional group]]s in the condensed formulas such as [[aldehyde]] as CHO, [[carboxylic acid]]s as {{chem2|CO2H}} or COOH, [[ester]]s as {{chem2|CO2R}} or COOR. However, the use of condensed formulas does not give an immediate idea of the molecular geometry of the compound or the number of bonds between the carbons, it needs to be recognized based on the number of atoms attached to the carbons and if there are any charges on the carbon.<ref>{{Cite journal |last=Liu |first=Xin |date=2021-12-09 |title=2.1 Structures of Alkenes |url=https://kpu.pressbooks.pub/organicchemistry/chapter/2-1-alkanes-structures-and-naming-nomenclature/ |language=en}}</ref>