Deux nouvelles structures polytypiques dans le système titane–soufre: 16H et 18H

The structures of two recently discovered polytypes of titanium sulphide have been determined. The structure of 18H, mainly built on a stacking sequence similar to that of 8H (3212), confirms the formation mechanism formerly suggested for TiS_1.7 hexagonal polytypes. In the same way, the stacking sequence of 16H provides some evidence of a 4H → 12H transformation producing rhombohedral polytypes. The experimental data supporting these conclusions are presented in this paper.