Über die Dialkaliacetylendicarboxylate Na2(C2(COO)2)(H2O)4 und K2(C2(COO)2)(H2O) / On Dialkali Acetylenedicarboxylates Na2(C2(COO)2)(H2O)4 and K2(C2(COO)2)(H2O)

Abstract

AbstractFrom aqueous solutions containing acetylenedicarboxylic acid and Na2CO3 or KOH single crystals of Na2(C2(COO)2)(H2O)4 (P21/n, Z = 2) and K2(C2(COO)2)(H2O) (P1̅, Z = 2) were obtained by slow evaporation of the solvent. In Na2(C2(COO)2)(H2O)4 the sodium atom is co-ordinated almost octahedrally by three water molecules and three oxygen atoms of the carboxylate ligands. These octahedra are connected to layers, which are held together by hydrogen bonds. In K2(C2(COO)2)(H2O) two crystallographic distinct potassium ions exist both seven co-ordinate by oxygen atoms stemming from water molecules and carboxylate ligands. These KO7 polyhedra are linked to a threedimensional structure by the bifunctional carboxylate anions and the water molecules.