(2H)2-2C type superstructure of TiS1.62, determined by high-resolution electron microscopy

A superstructure of TiS_1.62 is determined by 100 kV high-resolution electron microscopy, in which the arrangement of metal vacancies is obtained from structure images. The crystal has monoclinic symmetry (pseudo-hexagonal) with lattice parameters a = 11.9, b = 6.85, c = 11.5Å, β = 90°. The space group is considered as $\text{F2}\text{m}$. Metal vacancies are confined to every second metal layer and ordered within the partly filled metal layer, resulting in formation of a (2H)₂2C type of superstructure. The ordered metal vacancy layers are arranged in 2C-type stacking sequence along the c axis, while sulfur atoms are arranged in 2H-type stacking sequence along the c axis.