Divalent Titanium: The Halides ATiX 3 (A = K, Rb, Cs; X = Cl, Br, I)

Within the 3×3 library of ternary alkali halides of titanium(II), ATiX 3 (A = K, Rb, Cs; X = Cl, Br, I), five compounds were synthesized by conproportionation reactions. Single crystals were grown and the structures determined by single‐crystal X‐ray techniques. The halides ATiX 3 crystallize either with the so‐called hexagonal perovskite type structure (CsNiCl 3 , 2H), or with the so‐called KNiCl 3 ‐type of structure. This latter type allows two structural degrees of freedom. First, a shift of the colums of face‐sharing [TiCl 6 ] octahedra against each other and, secondly, a rotation of these colums relative to each other. With these degrees of freedom, individual coordination spheres are designed for the alkali‐metal cations A + .