A sulfur-bridged sandwich cubane-type molybdenum-antimony cluster [(H2O)(9)Mo3S4SbS4Mo3(H2O)(9)](8+) (2) has been synthesized through the reaction of incomplete cubane-type molybdenum cluster [Mo3S4(H2O)(9)](4+) (1) With antimony metal, and has been isolated as 2(pts)(8). 24H(2)O (2.pts) (Hpts = p-toluenesulfonic acid), whose structure has been characterized by X-ray crystallography. Crystal data of 2 pts : triclinic, space group P (1) over bar, a 14.468(3) Angstrom, b = 18.531(5) Angstrom, c = 13.713(6) Angstrom, alpha = 105.26(2)degrees, beta = 119.71(1)degrees, gamma = 72.48(3)degrees, V = 3016(1) Angstrom(3), Z = 1, D-calcd = 1.696 g cm(-3), D-obsd = 1.72 g cm(-3), R(R-w) = 4.7 (7.5) for 6593 reflections (I> 2.0 sigma(1)). The Mo-Sb distances (3.68[2]) Angstrom) are much longer than the Mo-Mo (2.717[7] Angstrom) distances. Peak positions and epsilon values (lambda(max) nm (epsilon, M-1 cm(-1))) of the electronic spectrum of 2 pts in 2 M HCl are 384 (13 220), 625 (10 440), and 700 (10 080). The Sb-121 Mossbauer parameters (delta = -2.64 mm s(-1), e(2)qQ = 18.1 mm s(-1), eta = 0.29), and the binding energies (eV) and full widths at half-maximum (in parentheses, eV) obtained from XPS spectrum. (Sb-3d3/2, 540.3(2.3) Mo-3d3/2, 233.2(2.1); Mo-3d5/2, 230.2(1.9); (C-1s = 285.0)) of 2 pts indicate that the oxidation number of antimony is III, and the mean oxidation number of molybdenum is +3.5.