Talk:Unit cell

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The contents of the Primitive cell page were merged into Unit cell on 9 May 2021. For the contribution history and old versions of the redirected page, please see its history; for the discussion at that location, see its talk page.

From the International Tables for Crystallography, Volume A (page 24-25):

The definition of a lattice as given in Section 1.3.2.1 states that a lattice consists precisely of the integral linear combinations of the vectors in a lattice basis. However, in crystallographic applications it has turned out to be convenient to work with bases that have particularly nice metric properties. For example, many calculations are simplified if the basis vectors are perpendicular to each other, i.e. if the metric tensor has all non-diagonal entries equal to zero. Moreover, it is preferable that the basis vectors reflect the symmetry properties of the lattice. By a case-by-case analysis of the different types of lattices a set of rules for convenient bases has been identified and bases conforming with these rules are called conventional bases. The conventional bases are chosen such that in all cases the integral linear combinations of the basis vectors are lattice vectors, but it is admitted that not all lattice vectors are obtained as integral linear combinations.

The conventional unit cell is often not the smallest unit cell with the point symmetry of the lattice. Counterexample: the Wigner-Seitz cell has the point symmetry of the lattice, and is smaller. The benefit of the conventional cell is that they are the unit cells crystallographers uses these in practice, and that way there's no need to define centering conventions every time. They might seem unique since they're nearly universal, but they're derived from convention, not by theorem. 〈 Forbes₇₂ | Talk 〉 03:02, 23 July 2021 (UTC)[reply]

@Goodphy: Please don't delete reliable sources without giving a clear justification. I see your intention was to improve the definition of the unit cell. You put your new definition next to the Ashcroft and Mermin citation, but that textbook doesn't actually define unit cells as a "space unit". You also revered my addition of the rest of the missing Bravais lattices, why? Let's discuss the definitions and make sure it corresponds to reliable sources. 〈 Forbes₇₂ | Talk 〉 07:28, 31 July 2021 (UTC)[reply]

There exist two wikidata objects, one for unit cell and one for primitive cell. This article is linked to primitive cell, but all other languages except hu link to unit cell. This leads to the disadvantage that they cannot be found easily. I'm not very familiar with the topic, but would it maybe be better to link this article to primitive cell as well? --Tinux (talk) 20:15, 18 March 2022 (UTC)[reply]

This article was the subject of a Wiki Education Foundation-supported course assignment, between 23 January 2024 and 9 May 2024. Further details are available on the course page. Student editor(s): An.cellkid (article contribs).

— Assignment last updated by An.cellkid (talk) 23:21, 22 February 2024 (UTC)[reply]