The azamolybdatranes ClMo(Me(3)SiNCH(2)CH(2))(3)N, 2a, and ClMo(t-BuMe(2)SiNCH(2)CH(2))(3)N, 2b, were prepared by the reaction of MoCl3(THF)(3) and the corresponding lithiated tetramines. The mu(eff) for 2a is 2.35 mu(B). This compound was structurally characterized in the solid state by X-ray diffraction. Crystal data : cubic, a = 17.199(1) Angstrom, V = 5087.6(11) Angstrom(3), Z = 8, space group Pa3 $$($) over bar, R = 2.7%.