Cover illustration: The independent molecular components of (E)-3-(4-methylphenyl)-2-(2-thienyl)acrylonitrile, showing molecule 1 (left) and the four orientations of molecule 2 across a site of 2/m symmetry at (0, 0, ½) (right). Displacement ellipsoids are drawn at the 30% probability level. See Cobo, Quiroga, Cobo & Glidewell [Acta Cryst. (2009), C65, o444-o446].
The crystal structure of lithium magnesium chloride heptahydrate was determined under ambient conditions. It belongs to the group of carnallites and is formed during evaporation from lithium-rich brines.
The title compounds crystallize in the orthorhombic space group Pnma in the CaFe2O4 structure type. They exhibit a three-dimensional channel structure of LnSe6 octahedra, with Ba atoms occupying the channels.