The alkaline metal ore-silicates A(6)[Si3O9] and A(6)[Si2O7] (A = Rb, Cs):Preparation and crystal structure

The title compounds were synthesized via reaction of quartz and AO(2) (A = Rb, Cs) with the elemental alkali metals. Their crystal structures were det ermined on the basis of single crystal X-ray data. All compounds crystalliz e in the monoclinic system with space group P2(1)/c and lattice constants a = 656.0(1)/684.7(3), b = 1329.7(3)/1375.7(4), c = 1647.6(3)/1703.6(8) pm, beta = 107.78(3)/108.23(2)degrees, Z = 4(A(6)[Si3O9], A = Rb/Cs) and a = 66 8.59(8)/711.4(1), b = 911.37(9)/952.1(2). c=1121.09(9)/1192.7(7) pm. beta = 125.52(9)/126.22(3)degrees. Z=2(A(6)[Si2O7], A = Rb/Cs) respectively. The r ubidium and cesium compounds are isotypic with the corresponding potassium silicates.