Synthesis and molecular and crystal structure of K-4.5{[Mo-3(mu(3)-Te)(mu(2)-Te-2)(3)(CN)(6)]I}I-1.5 center dot 3H(2)O and Cs-3{[Mo-3(mu(3)-Te)(mu(2)-Te-2)(3)(CN)(6)]I}center dot 2H(2)O

Crystal structures of two new compounds containing trigonal tellurium-bridg ed cluster fragments [Mo-3(mu (3)-Te)(mu (2-)-Te-2)(3)](4+) were investigat ed. Crystal data for K-4.5{[Mo-3(mu (3)-Te)(mu (2)-Te-2)(3)(CN)(6)]I}I-1.5. 3H(2)O: space group P3c1, Z = 4, a = 13.280(1), c = 23.800(3) Angstrom, V = 3635.0(6) Angstrom (3), d(calc) = 3.432 g/cm(3), R-1 = 0.0335, wR2 = 0.091 2 for 1378 I-hkl>2 sigma (1) from 3545 meausred I-hkl; for Cs-3{[Mo-3(mu (3 )-Te)(mu (2)-Te-2)(3)(CN)(6)]I}.2H(2)O: space group P2(I)/n, Z = 2, a = 9.6 50(2), b = 22.297(5), c = 27.446(7) Angstrom, beta = 94.10(2)degrees, V = 5 890(2) Angstrom (3), d(calc) = 4.273 g/cm(3), R-1 = 0.0384, wR(2) = 0.0744 for 957 I-hkl>2 sigma (I) from 3758 measured I-hkl (Enraf-Nonius CAD-4 diff ractometer, lambda MoKalpha, graphite monochromator). In both compounds, io nic pairs {[Mo3Te7(CN)(6)]I}(3-) with Te-ax...Gamma distances of 3.358-3.67 6 Angstrom are formed. In the potassium salt, the {[Mo3Te7(CN)(6)]I}(3-) an ion pairs are linked by the additional Te-eq...Gamma short contacts of 3.46 0 Angstrom into two-dimensional corrugated layers perpendicular to the c ax is of the unit cell. The structure of the cesium salt is ionic with interst itial H2O molecules and double-layer closest packing of anions.