Zur Kenntnis von Be[C2(COO)2] · 4 H2O — Ein durch starke Wasserstoffbrückenbindungen stabilisiertes anorganisches Derivat der Acetylendicarbonsäure / On Be[C2(COO)2] · 4 H2O — An Inorganic Derivative of Acetylenedicarboxylic Acid Stabilized by Strong Hydrogen Bonding

Abstract

Colorless orthorhombic single crystals of Be[C2(COO)2] · 4 H2O were grown in aqueous silica gel. Space group Cmcm, α = 1004.7(1), b = 675.0(1), c = 1262.4(2) pm, Rg = 0.0264. The crystal structure consists of Be(H2O)4 2+ tetrahedra and planar [C2(COO)2]2- anions linked together by strong asymmetric hydrogen bonds. A layer-like arrangement extending parallel (010) made up by [C2(COO)2]2- anions and hydrogen bound water molecules of the Be(H2O)4 2+ tetrahedra is the primary structural feature of Be[C2(COO)2] · 4H2O. These layers are stacked and interlinked by coordinative bonds between Be2+ and H2O to yield a rigid three-dimensional framework. Thermal decomposition commences with endothermic loss of water of crystallisation at 160 °C followed by several steps of exothermic degradation yielding finally a soot-like amorphous residue.