X-ray crystallographic study and thermogravimetric analysis of tetrammine-carbonatocobalt(III) nitrate hemihydrate, [Co(NH3)4CO3]NO3 • 0.5H2O

The crystal structure of tetrammine-carbonatocobalt(III) nitrate hemihydrate, [Co(NH3)(4)CO3]NO3. 0.5H(2)O, was solved by direct methods from single crystal X-ray diffraction data. The size of the single crystal used was 0.075 x 0.075 x 0.007 mm(3). The structure is monoclinic, space group P2(1)/n (No. 14), with the lattice parameters a = 7.4519(4), b = 22.647(1), c = 10.4103(5) Angstrom, beta = 92.052(1)degrees and Z = 8. The structure has two independent Co(NH3)(4)CO3 coordination octahedra. The Co-N bonds are in the range 1.944(6)-1.976(5) Angstrom and the Co-O bonds in the range 1.903(4)-1.918(5) Angstrom. Indexing of the X-ray powder pattern gave the lattice parameters a = 7.482(4), b = 22.667(6), c=10.540(4) Angstrom, beta = 91.37(4)degrees, using lambda = 1.5406 Angstrom. Thermogravimetric analysis of [Co(NH3)(4)CO3]NO3. 0.5H(2)O show a complete decomposition to Co3O4 at 430 degrees C.