Editing Haworth projection

{{Short description|Method for writing structural formulas of monosaccharide molecules}}
[[Image:Haworth projection of α-D- and α-L-Glucopyranose.svg|class=skin-invert-image|thumb|275px|right|Haworth projection of the structures for [[Glucose|α-<small>D</small>-glucopyranose]] and [[L-Glucose|α-<small>L</small>-glucopyranose]]]] 

In [[chemistry]], a '''Haworth projection''' is a common way of writing a [[structural formula]] to represent the [[monosaccharide#Cyclisation|cyclic structure]] of [[monosaccharide]]s with a simple three-dimensional perspective. A Haworth projection approximates the shapes of the actual molecules better for [[Furanose|furanoses]]—which are in reality nearly planar—than for [[Pyranose|pyranoses]] that exist in solution in the chair conformation.<ref>{{Cite book |last=Campbell |first=Mary K. |url=https://www.worldcat.org/oclc/651905707 |title=Biochemistry |date=2012 |publisher=Brooks/Cole, Cengage Learning |others=Shawn O. Farrell |isbn=978-0-8400-6858-3 |edition=7th |location=Belmont, CA |page=456 |chapter=16 |oclc=651905707}}</ref> [[Organic chemistry]] and especially [[biochemistry]] are the areas of chemistry that use the Haworth projection the most.

The Haworth projection was named after the British chemist Sir [[Norman Haworth]].<ref>{{cite book |last1=Haworth |first1=Walter Norman |title=The Constitution of Sugars |date=1929 |publisher=Edward Arnold & Co. |location=London, England}}</ref>

A Haworth projection has the following characteristics:<ref>{{GoldBookRef|title=Haworth representation|file=H02749}}</ref>
* [[Carbon]] is the implicit type of atom. In the example on the right, the atoms numbered from 1 to 6 are all carbon atoms. Carbon 1 is known as the [[anomer]]ic carbon.
* [[Hydrogen]] atoms on carbon are implicit. In the example, atoms 1 to 6 have extra hydrogen atoms not depicted.
* A thicker line indicates atoms that are closer to the observer. In the example on the right, atoms 2 and 3 (and their corresponding OH groups) are the closest to the observer. Atoms 1 and 4 are further from the observer. Atom 5 and the other atoms are the furthest.
*The groups below the plane of the ring in Haworth projections correspond to those on the right-hand side of a [[Fischer projection]]. This rule does not apply to the groups on the two ring carbons bonded to the endocyclic oxygen atom combined with hydrogen.

== See also ==
* [[Skeletal formula]]
* [[Natta projection]]
* [[Newman projection]]

== References ==
<references />

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[[Category:Carbohydrate chemistry]]
[[Category:Carbohydrates]]
[[Category:Stereochemistry]]


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