AbstractThe compoundstrans‐[Ta6Cl12(OH)4(H2O)2] · 10 H2O1, (NMe4)2[Ta6Cl12(OH)6] · 21 H2O2and Na2[Ta6Cl12(OH)6] · 16 H2O3containing octahedral tantalum chloro clusters were isolated from alkaline methanol/water solutions of [Ta6Cl12]4+. Crystal structures were solved for1and2.Crystal data:1, monoclinic, space group P21/c (No. 14), a = 938.5(2) pm, b = 1220.3(2) pm, c = 1391.7(4) pm, β = 103.87(2)°, V = 1547.5(6) × 106pm3, Z = 2;2, rhombohedral, space group R3(No. 148), a = 1201.4(2) pm, c = 3110.8(6) pm, V = 3888.5(12) × 106pm3, Z = 3;3, cubic F lattice, a = 1451(2) pm, V = 3055(13) × 106pm3, Z = 4.The cluster in1contains the neutral, mixed‐coordinatedtrans‐[Ta6Cl12(OH)4(H2O)2] cluster with TaOH and TaOH2distances 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 of2is built of [Ta6Cl12(OH)6]2−anions, NMe4+cations and water molecules, the latter linked