Last evening had a nice chat with a friend of mine from the Materials Science Department. At a certain point we came to a discussion about the crystal structure and ways to represent it. As my counterpart was pointing out that it’s enough to give chemical composition and a space group to define the crystal structure, he stated that Strukturbericht notation is superfluous and useless.
We had a long and interesting discussion, which I omit here. However, we came to an agreement that at least in the following phrase, using the Strukturbericht notation is good, as it gives the shortest and clearest explanation of what is going on:
“Ni2MnAl exhibits structural transitions between the L21↔ B2 ↔ A2 phases at 990 K and 1220 K, respectively.”
Strukturbericht is a classification of the crystal structures, where a codename is associated with a certain “well-known” crystal structure, exhibiting certain space group. E.g. B2 stands for CsCl cell, Fm-3m space group. The problem of this classification is loose categorization (e.g. A – pure elements, B – AB_2 compounds) and thus uninformative codenames (if I don’t know what is A2 or B2, I cannot deduce it.)
Another method, using codenames for the crystal structure, is Pearson symbol. However, it can lead to ambiguous names.