Wikipedia:Good article reassessment/X-ray crystallography/1
The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
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- 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)
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)
- Saw the post at WT:MOLBIO. Woof, this article is a beast. Just in the History section this article needs some heavy lifting:
- 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.
- 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)
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.