MAGNETIC-SUSCEPTIBILITY ANALYSIS OF MIXED-METAL CUBANE-TYPE CLUSTER COMPLEXES, IS(TRI(AQUA)MOLYBDENUM)AQUAIRON](4-TOLUENSULFONATE HEPTAHYDRATE AND I(AQUA)MOLYBDENUM)AQUANICKEL](4+)P-TOLUENSULFONATE HEPTAHYDRATE()P)

Magnetic susceptibilities of the tetranuclear cluster complexes [Mo3Fe S4(H-2O)(10)](CH3C6H4SO3)(4) . 7H(2)O (1) and [Mo3NiS4(H2O)(10)](CH3C6 H4SO3)(4) . 7H(2)O (2) containing molybdenum ions of the 4d transition metals and the Fe or Ni ion of the 3d transition metals are measured at temperatures from similar to 2 to 270 K. The magneti c susceptibili ties are analyzed on the basis of the Vector model formalism of Kambe. We used the models containing four metal ions Mo-3(IV,III,III) and Fe (II), and Mo,(IV,III,nl) and Ni(II), respectively. The exchange integr als are estimated as J(1(Mo-Mo))/k(B) = -25 K and J(2(Mo-Fe))/k(B) = - 75 K for 1, and J(1(Mo-Mo))/k(B) = -35 K and J(2(Mo-Ni))/k(B) = -60 K (A(Mo) = 1.1, k(Mo) = 60%, A(Ni) = 1.2, k(Ni) = 100%; A is the paramet er for orbital-angular momentum, k is an orbital reduction factor) for 2. These parameters are in excellent agreement with the experimental data of the magnetic susceptibilities of both cluster complexes.