“…[3] Formally, a total substitution of Cu by Na has just been achieved recently. [4] Not much literature is yet known about Na 2 ZnSnS 4 , but, however, according to the published articles [4,5] on synthesis, crystal structure, and properties of Na 2 ZnSnS 4 , it seems to crystallize in a chalcopyrite-derived crystal structure with an ordered arrangement of the cations [4] or the stannitetype structure, [5] both tetragonal, corresponding to Cu 2 ZnSnS 4 [6] and Cu 2 FeSnS 4 , [7] respectively. Both articles are primarily focused on the material properties of Na 2 ZnSnS 4 such as optical, electronic, and electrical ones.…”