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The solvent-free reaction of terbium metal with an imidazole melt (C 3 H 4 N 2 , ImH) yields single-crystalline ∞ 3 [Tb(Im) 3 ]@NH 3 (Im -) C 3 H 3 N 2 -, imidazolate anion) and hydrogen. Both N atoms of the imidazolate rings coordinate η 1 to terbium cations, thereby forming a homoleptic three-dimensional network. The Tb 3+ ions exhibit complete nitrogen coordination, resulting in trigonal prisms as coordination polyhedra and C.N. ) 6. The network contains cavities large enough to take up NH 3 molecules, the latter formed by the partial decomposition reaction of the amine ligand in the melt reaction. Ammonia can be removed thermally or over time without decomposition of the network. Unsubstituted imidazole can thus be utilized for crystal engineering and the formation of rare earth amide network structures. The compound exhibits an amazingly strong green emission. The emission spectrum shows the typical Tb 3+ f-f transitions; additionally, an efficient ligand f Tb 3+ energy transfer is observed.

The dehydration of Ca(SCN)2∙4H2O yields single crystals of Ca(SCN)2 ∙ 2 H2O as well as of Ca(SCN)2. Ca(SCN)2 ∙ 2 H2O crystallizes with a hitherto unknown structure (orthorhombic, Pnma, Z = 4, a = 1280.1(2), b = 790.3(1), c = 726.9(1) pm, Rall = 0.0430). The Ca2+ ions are surrounded by four SCN− ions and four water molecules. The polyhedra are connected to chains along [010] via common oxygen atoms. The SCN− ions connect these chains to a three-dimensional network so that each thiocyanate group is linked to two Ca2+ ions. Hydrogen bonding with sulfur atoms as acceptors is observed. The crystal structure of Ca(SCN)2 (monoclinic, C2/c, Z = 4, a = 961.7(2), b = 642.4(2), c = 787.2(2) pm, Rall = 0.0673) consists of alternating layers of Ca2+ and SCN− ions. The cations are surrounded by four sulfur and four nitrogen atoms in form of a square antiprism. According to 3∞[Ca(SCN)8/4] each SCN− ion connects four Ca2+ ions with each other. Thermal investigations show a phase transition of Ca(SCN)2 ∙ 4 H2O followed by dehydration to Ca(SCN)2 which finally decomposes yielding CaS. IR and Raman measurements have been performed and the resulting frequencies assigned and discussed.