Editing Chemical structure (section)

===Structural elucidation===
The methods by which one can determine the structure of a molecule is called ''structural elucidation''. These methods include:

* concerning only connectivity of the atoms: [[spectroscopy|spectroscopies]] such as [[nuclear magnetic resonance]] ([[proton NMR|proton]] and [[carbon-13 NMR]]), and various methods of [[mass spectrometry]] (to give overall molecular mass, as well as fragment masses). Techniques such as [[absorption spectroscopy]] and the [[vibrational spectroscopy|vibrational spectroscopies]], [[infrared spectroscopy|infrared]], and [[Raman spectroscopy|Raman]], provide, respectively, important supporting information about the numbers and adjacencies of multiple bonds, and about the types of functional groups (whose internal bonding gives vibrational signatures); further inferential studies that give insight into the contributing electronic structure of molecules include [[cyclic voltammetry]] and [[X-ray photoelectron spectroscopy]].
* concerning precise metric three-dimensional information: can be obtained for gases by [[gas electron diffraction]] and [[rotational spectroscopy|microwave (rotational) spectroscopy]] (and other rotationally resolved spectroscopy) and for the crystalline solid state by [[X-ray crystallography]]<ref name=":0">{{cite book |last=Rankin, David W. H. |title=Structural methods in molecular inorganic chemistry |others=Morrison, Carole A., 1972-, Mitzel, Norbert W., 1966- |date=January 2, 2013 |publisher=Wiley |location=Chichester, West Sussex, United Kingdom |isbn=978-1-118-46288-1 |oclc=810442747 |url=https://search.worldcat.org/title/810442747}}</ref> or [[neutron diffraction]]. These technique can produce three-dimensional models at atomic-scale [[optical resolution|resolution]], typically to a precision of 0.001 Å for distances and 0.1° for angles (in unusual cases even better).<ref>{{cite book |last=Glusker, Jenny Pickworth |title=Crystal structure analysis for chemists and biologists |date=1994 |publisher=VCH |others=Lewis, Mitchell; Rossi, Miriam |isbn=0-89573-273-4 |location=New York |oclc=25412161 |url=https://search.worldcat.org/title/25412161}}</ref><ref name=":0"/>

Additional sources of information are: When a molecule has an unpaired electron spin in a [[functional group]] of its structure, [[ENDOR]] and [[electron-spin resonance]] spectroscopes may also be performed. These latter techniques become all the more important when the molecules contain metal atoms, and when the crystals required by crystallography or the specific atom types that are required by NMR are unavailable to exploit in the structure determination. Finally, more specialized methods such as [[electron microscopy]] are also applicable in some cases.