Synthesis, crystal structure and characterization of two new organic bismuthate(III) compounds: [C6H18O]2Bi2X10·2H2O (X = Br, Cl)

Abstract

The synthesis and the structures of two new compounds with the general formula [C6H18N2O]2Bi2X10·2H2O (X = Br, Cl) are reported. They crystallize in the triclinic system and are isostructural. Crystal structures were solved and refined to R = 0.064, 0.048 and Rw = 0.15, 0.13 using 3392, 3679 independent reflections for the Cl and Br derivatives, respectively. The atomic arrangement can be described by inorganic chains along the [100] direction. These chains are themselves interconnected by means of N–H···X (X = Cl, Br) originating from the [C6H18N2O]2+ entities, to form three-dimensional network. The organic part consists of one organic cation which orients its two amine groups to the neighboring anions. The inorganic entity is made up of [Bi2X10]4− dimers composed of two equivalent irregular octahedra sharing one edge. The oxygen atoms of the water molecules (OW) act as donor (O–H···X) and acceptor (N–H···O) of hydrogen bonds. The nature of the distortion of the inorganic polyhedra can be attributed to the stereoactivity of the Bi(III) lone electron pair. Raman and infrared spectra at room temperature were recorded in the 500–100 and 4000–400 cm−1 frequency regions, respectively. This study confirms the presence of the organic cation [C6H18O]2+ and the bioctahedron [Bi2X10]4−. The calorimetric study shows that the title compound is stable until 384 K.