Ab initio calculation of the tetracarbonatoscandate-ion in Na-5[Sc(CO3)(4)] center dot 2H(2)O. Single crystal structure determination, vibrational spectra, and thermal decomposition

Normal modes of the tetracarbonatoscandate-ion, [Sc(CO3)(4)](5-), were dete rmined by ab initio calculations and were compared with experimental data o f Infrared- and Raman-spectra of the compound Na-5[Sc(CO3)(4)] . 2 H2O. A n ecessary redetermination of the structure with single crystal x-ray diffrac tion data (tetragonal, P42(1)c (Nr. 114), Z = 2, a = 746,37(4) pm, c = 1157 ,0(2) pm, V-EZ = 644,5(1) 10(6) pm(3)) allows the discussion of existing hy drogen bonds. Determination of the thermal behaviour indicates a two-stage decomposition reaction, but no corresponding intermediate could be isolated .