Cover illustration: The molecular packing in chlorotris(N,N'-dicyclohexylthiourea-S)tellurium(II) chloride, with hydrogen bonds indicated by dashed lines. For clarity, only the C atoms (dotted circles) joined to the main structural unit in the cyclohexyl groups are shown. See Husebye, Törnroos & Zhu [Acta Cryst. (2001), C57, 854-856].
An isomer of B20H26, isolated from the autolysis of nido-B10H14 in a silent electrical discharge, is shown to be the title compound 1,1′-bis(nido-decaboranyl). The molecule has crystallographic inversion symmetry and a long intercage B—B bond of 1.704 (3) Å.
The Ag+ ions in the title compounds are tetrahedrally coordinated by the S atoms of four thiocyanate groups, which act as terminal or 1,1-μ-bridging ligands. The anions in K[Ag(SCN)2] form a two-dimensional polymeric network containing Ag2S2 and Ag6S6 rings.
The monoclinic superstructure of Ce-doped SrMgF4 can be described as a stack of perovskite-type slabs in which MgF6 octahedra are rotated in a complicated manner. Sr atoms are shifted from ideal positions to fit in the space formed by the six MgF6 octahedra of one slab and one MgF6 octahedron of a neighbouring slab.