Article (edit | visual edit | history) · Article talk (edit | history) · Watch • Watch article reassessment page • Most recent review

Result: Per the discussion at WT:GAR#Please keep topical limits in mind and below, this chemistry article is far below the GA criteria. ~~ AirshipJungleman29 (talk) 18:24, 15 February 2023 (UTC)[reply]

GA from 2008. There's some uncited information including

• Finally, X-ray crystallography had a pioneering role in the development of supramolecular chemistry, particularly in clarifying the structures of the crown ethers and the principles of host–guest chemistry. X-ray diffraction is a very powerful tool in catalyst development. Ex-situ measurements are carried out routinely for checking the crystal structure of materials or to unravel new structures. In-situ experiments give comprehensive understanding about the structural stability of catalysts under reaction conditions. In material sciences, many complicated inorganic and organometallic systems have been analyzed using single-crystal methods, such as fullerenes, metalloporphyrins, and other complicated compounds. Single-crystal diffraction is also used in the pharmaceutical industry, due to recent problems with polymorphs. The major factors affecting the quality of single-crystal structures are the crystal's size and regularity; recrystallization is a commonly used technique to improve these factors in small-molecule crystals. The Cambridge Structural Database contains over 1,000,000 structures as of June 2019; over 99% of these structures were determined by X-ray diffraction.
• which is on the scale of covalent chemical bonds and the radius of a single atom. Longer-wavelength photons (such as ultraviolet radiation) would not have sufficient resolution to determine the atomic positions. At the other extreme, shorter-wavelength photons such as gamma rays are difficult to produce in large numbers, difficult to focus, and interact too strongly with matter, producing particle-antiparticle pairs. Therefore, X-rays are the "sweetspot" for wavelength when determining atomic-resolution structures from the scattering of electromagnetic radiation.
• The Electron and Neutron diffraction section.
• Each spot is called a reflection, since it corresponds to the reflection of the X-rays from one set of evenly spaced planes within the crystal. For single crystals of sufficient purity and regularity, X-ray diffraction data can determine the mean chemical bond lengths and angles to within a few thousandths of an angstrom and to within a few tenths of a degree, respectively. The atoms in a crystal are not static, but oscillate about their mean positions, usually by less than a few tenths of an angstrom. X-ray crystallography allows measuring the size of these oscillations.

And many more. Onegreatjoke (talk) 21:30, 7 February 2023 (UTC)[reply]

Saw the post at WT:MOLBIO. Woof, this article is a beast. Just in the History section this article needs some heavy lifting:

1. Too much detail/Not enough detail - some of this is undue and should be merged into the History section of X-ray or trimmed. Some is not about History and should be moved to the Theory section (e.g. the top of the "X-ray diffraction" subsection). Partly it's to make the section more readable, but also we need to make space to discuss the post-1920 history of crystallography in greater detail. This history section would make you think we stopped using X-ray crystallography 100 years ago. See this (very long) review to fill in some of the gaps.
2. Wrong citations - The History section is written like a scientific review article. The references are links to scientific works of the distant past, rather than actually supporting the claim that so-and-such discovered this-and-that.

I haven't made it further yet. But unless someone else is interested in working on this, I'm afraid it'll be a task beyond the time I have available. Ajpolino (talk) 23:11, 7 February 2023 (UTC)[reply]