Crystal structures of trans-[Ta6Cl12(OH)(4)(H2O)(2)]center dot 10H(2)O and (NMe(4))(2)[Ta6Cl12(OH)(6)]center dot 21H(2)O

The compounds trans-[Ta6Cl12(OH)(4)(H2O)(2)]. 10H(2)O 1, (NMe(4))(2)[Ta6Cl12(OH)(6)]. 21 H2O 2 and Na-2[Ta6Cl12(OH)(6)]. 16H(2)O 3 containing octahedral tantalum chloro clusters were isolated from alkaline methanol/ water solutions of [Ta6Cl12](4+). Crystal structures were solved for 1 and 2. Crystal data: 1, monoclinic, space group P2(1)/c (No. 14), a = 938.5(2) pm, b = 1220.3(2) pm, c = 1391.7(4) pm, beta = 103.87(2)degrees, V = 1547.5(6)x10(6) pm(3), Z = 2; 2, rhombohedral, space group R3 (No. 148), a = 1201.4(2) pm, c = 3110.8(6) pm, V = 3888.5(12)x10(6) pm(3), Z = 3; 3, cubic F lattice, a = 1451(2) pm, V = 3055(13)x10(6) pm(3), Z = 4. The cluster in 1 contains the neutral, mixed-coordinated trans-[Ta6Cl12(OH)(4)(H2O)(2)] cluster with Ta-OH and Ta-OH2 distances of 210.4(5) pm and 214.5(5) pm, respectively. One coordinated H2O molecule from one cluster and a coordinated OH- group from a neighbouring cluster form H3O2- intercluster bridges with the O ... H-O distance 253.7(7) pm. Twelve Ta-Cl (bridging) distances range from 244.1(2) to 245.2(2) pm. The structure of 2 is built of [Ta(6)C1(12)(OH)(6)](2-) anions, NMe(4)(+) cations and water molecules, the latter linked to the anions by hydrogen bonds.