Mechanochemical synthesis and crystal structure evaluation of Na2ZnSnS4

Abstract Phase‐pure and highly crystalline Na 2 ZnSnS 4 was prepared via a mechanochemical synthesis route. It crystallizes in the kesterite‐type structure. The unusual large Debye‐Waller factors of the sodium atoms were analyzed in detail, respecting also group‐theoretical aspects. The results point to the existence of static disorder, mainly to the presence of various patterns of sodium ordering on a local scale. This is confirmed by quantum‐chemical calculations at hybrid density‐functional theory level. The dynamic atomic displacements due to phonons are much smaller than the observed Debye‐Waller factors.