What is Crystallography?
'''Crystallography''' is the study of the arrangement of [[atom]]s in [[solid]]s that are mostly in three dimensional pattern.<ref>Howard M. & D. ''Introduction to crystallography and mineral crystal systems''. [http://www.rockhounds.com/rockshop/xtal/part1.shtml] {{Webarchive|url=https://web.archive.org/web/20160407061859/http://www.rockhounds.com/rockshop/xtal/part1.shtml |date=2016-04-07 }}</ref> Before the development of [[X-ray crystallography]], the study of [[crystal]]s was based on their [[geometry]]. This involves measuring the [[angle]]s of crystal faces, and establishing the [[symmetry]] of the crystal in question. == X-ray diffraction == Crystal structure is now found by analysis of the [[diffraction]] patterns of a sample targeted by a beam of some type. The technique was jointly invented by Sir [[William Bragg]] (1862–1942) and his son Sir [[Lawrence Bragg]] (1890–1971), who jointly won the [[Nobel Prize in Physics]] for 1915. Lawrence Bragg was the youngest to become a Nobel Laureate. He was the Director of the [[Cavendish Laboratory]], [[Cambridge University]], when the discovery of the structure of [[DNA]] was made by [[James D. Watson]] and [[Francis Crick]] in February 1953.<ref>{{Cite web|title=X-ray diffraction {{!}} physics|url=https://www.britannica.com/science/X-ray-diffraction|access-date=2021-04-08|website=Encyclopedia Britannica|language=en}}</ref> [[X-ray]]s are most commonly used, but for some purposes [[electron]]s or [[neutron]]s are used. Because of the different forms of interaction, the three types of radiation are suitable for different crystallographic studies. === Technique === Some materials studied using crystallography, [[protein]]s for example, do not always occur naturally as crystals. Normally such molecules are placed in solution and allowed to crystallize over days, weeks, or months. Once a crystal is obtained, data can be collected using a beam of [[radiation]]. Although X-ray equipment is commonplace, crystallography often uses special [[synchrotron light sou