Editing Structural formula (section)

{{short description|Graphic representation of a molecular structure}}
[[File:Cobalamin skeletal.svg|thumb|300px|Skeletal structural formula of [[Vitamin B12|Vitamin B<sub>12</sub>]]. Many [[Organic compound|organic molecules]] are too complicated to be specified by a [[molecular formula]].]]

The '''structural formula''' of a [[chemical compound]] is a graphic representation of the molecular structure (determined by [[structural chemistry]] methods), showing how the atoms are connected to one another.<ref>{{Cite book |last=Olmsted |first=John |url=https://books.google.com/books?id=1vnk6J8knKkC&pg=PA86 |title=Chemistry: The Molecular Science |last2=Williams |first2=Gregory M. |date=1997 |publisher=Jones & Bartlett Learning |isbn=978-0-8151-8450-8 |language=en}}</ref> The [[chemical bond]]ing within the molecule is also shown, either explicitly or implicitly. Unlike other [[chemical formula]] types,{{efn|Structural formula is a type of chemical formula.<ref>{{cite web | url = https://study.com/learn/lesson/chemical-formula-types-examples.html#section---ChemicalFormulaExamples | title = What are Chemical Formulas and How are They Used? | at = sec. Chemical Formula Examples | author = Denise DeCooman | date = 2022-04-08 | archive-url = https://web.archive.org/web/20220623095905/https://study.com/learn/lesson/chemical-formula-types-examples.html#section---ChemicalFormulaExamples | archive-date = 2022-06-23 | publisher = Study.com}}</ref>}} which have a limited number of symbols and are capable of only limited descriptive power, structural formulas provide a more complete geometric representation of the molecular structure. For example, many chemical compounds exist in different [[isomer]]ic forms, which have different [[enantiomer]]ic structures but the same [[molecular formula]]. There are multiple types of ways to draw these structural formulas such as: [[Lewis structure]]s, condensed formulas, [[skeletal formula]]s, [[Newman projection]]s, [[Cyclohexane conformation]]s, [[Haworth projection]]s, and [[Fischer projection]]s.<ref>{{Cite journal |last=Goodwin |first=W. M. |date=2007-04-13 |title=Structural formulas and explanation in organic chemistry |journal=Foundations of Chemistry |volume=10 |issue=2 |pages=117–127 |doi=10.1007/s10698-007-9033-2 |s2cid=93952251 |issn=1386-4238}}</ref>

Several systematic chemical '''naming''' formats, as in [[chemical database]]s, are used that are equivalent to, and as powerful as, geometric structures. These [[chemical nomenclature]] systems include [[Simplified molecular-input line-entry system|SMILES]], [[International Chemical Identifier|InChI]] and [[Chemical Markup Language|CML]]. These systematic chemical names can be converted to structural formulas and vice versa, but chemists nearly always describe a [[chemical reaction]] or [[chemical synthesis|synthesis]] using structural formulas rather than chemical names, because the structural formulas allow the chemist to visualize the molecules and the structural changes that occur in them during chemical reactions. [[Chemsketch|ChemSketch]] and [[ChemDraw]] are popular downloads/websites that allow users to draw reactions and structural formulas, typically in the Lewis Structure style.