Hochdrucksynthesen einiger Carbonate mit überkritischem CO2

Syntheses of Some Carbonates with CO₂ under High Pressures Carbonates of the alkali metals and of some transition metals are prepared from their solutions, hydroxides, or oxides by reactions with CO₂ using pressures of 600–4500 at and temperatures of 100– 400°C. The carbonates MnCO₃, FeCO₃, CoCO₃, NiCO₃, ZrCO₃ · 2H₂O, Th(CO₃)₂ · 0.5 H₂O and the carbonates of the alkali metals are characterized by infrared spectroscopy and X-ray investigations. The structures of Rb₂CO₃ (1) and Cs₂CO₃ (2) are presented. They are both monoclinic, space group P 2_1/c (No. 14) with a = 5.87 (1), 6.13 (2); b = 10.13 (1), 10.28 (2); c = 7.33 (1), 8.15 Å (2), β = 97.65° (1), 95.85° (2) and Z = 4.