Common Polytypes of SnS2 and SnSe2

Structural polytypism in SnS 2 and SnSe 2 crystals grown by a chemical transport reaction and from a melt was studied by the X-ray diffraction method with a Weissenberg camera. It was revealed that in each of SnS 2 and SnSe 2 the type 18 R with the Zhdanov symbol (1212) 3 and space group R \bar3 m is the most or second common polytype.