Talk:Liquid crystal

Technical flag gone, okay?
I made a stab at making the intro less technical (without being uninformative). I removed the 'technical' flag. I would encourage others to read what's there and put the technical flag back in if it is still too confusing. Kebes 16:57, 20 Apr 2005 (UTC)

Link to wrong Chandrasekhar at bottom of article. -Pat

Order parameter Q
If one wants to find out about the order parameter Q on wikipedia, one has to search quite hard; it is mentioned only in the odd article biaxial nematic. But a textbook presentation of Q and S, displaying some more math, might not belong here as "too technical". I am trying to work in at least a mention and a link to the Q concept In the vicinity of S. CyreJ (talk) 13:20, 3 February 2022 (UTC)

No minerals
The statement that liquid crystals have representatives is wrong. There are no minerals that are liquid crystals. The mentioned V2O5, is - among minerals - known as shcherbinaite, and it forms normal crystals, not liquid crystals. A mineral must be crystalline (not liquid-crystalline) to be a mineral. A prominent exception is natural quasicrystals (icosahedrite and decagonite) and, to some extent, time crystals, but most likely they will soon be grouped separately, just as mineraloids are.Eudialytos (talk) 17:04, 12 December 2022 (UTC)
 * I suspect what is meant is that the materials are crystalline minerals at the atomic level, but have liquid crystalline arrangements at a larger scale - such as discotic order among microscopic "plates" of clay particles. Thus liquid crystallinity "occurs in the mineral world" and other vague statements. Feel free to improve ambiguous statements (while trying to keep introductions concise), or, if it really says minerals *are* liquid crystalline in atomic crystal structure, remove.  CyreJ (talk) 12:02, 18 December 2022 (UTC)
 * Thanks for your answer. I won't correct anything in Wiki anymore, due to fraud behaviour and misunderstanding by some users (who were constantly shifting-back my corrections), some years ago.Eudialytos (talk) 22:29, 18 May 2023 (UTC)
 * Liquid-crystalline phenomena in some clays do not make them liquid crystals - they are true crystals with known symmetries (i.e, Bravais type, space group, etc.)Eudialytos (talk) 11:15, 21 May 2023 (UTC)

Update needed?
Seems like this article could benefit from a substantial review and update to reflect recent developments in LC physics? For example, no mention here of the ferroelectric nematic phase, nor twist/bend nematic phase, nor the various bent-core smectic phases. Any of these deserves description and space compared to, for example, metallomesogens. 88.97.9.193 (talk) 18:25, 20 January 2023 (UTC)

a-plate, c-plate?
Are these concepts specific to LCs? I only seem them in LC field. Very hard to find a straight definition of them anywhere. Wikipedia doesn't have one, although it has a page for q-plate, which seems like a related concept. 162.246.139.210 (talk) 16:41, 14 December 2023 (UTC)


 * These are general crystal optics terms for waveplates made of uniaxial crystals. In c-plate the optic axis is along the surface normal of the plate, and in a-plate it is along the plane of the plate. Here a and c refer to unit cell axes, see e.g. the first figure at hexagonal crystal family. Probably this definition can be found from some crystal optics textbook, and could be added to one of the related articles. Jähmefyysikko (talk) 20:58, 14 December 2023 (UTC)