The polyoxoanion incorporated [Mn(CO) 3 + } complex, (n-Bu 4 N) 2 [Mo 6 O 16 (OCH 3 ) 2 {HOCH 2 C(CH 2 O) 3 } 2 ·{Mn(CO) 3 } 2 ](1). has been synthesized by the reaction of (n-Bu 4 N) 4 [Mo 8 O 26 ] with Mn(CO) 5 Br in methanol, in the presence of C(CH 2 OH) 4 . The complex 1 has been characterized by IR, UV-Vis, X-ray single crystal diffraction, and TG. Crystal data for the complex 1: C 25 H 48 MnMo 3 NO 16 (1), Triclinic P . a=0.9405(3) nm, b=1.3351(4) nm, c=1.5455(4) nm, α= 103.206(5)°, β=102.165(5)°, γ=100.784(5)°, V=1.7896(9) nm 3 , Z=2, R 1 ,=0.0703, wR 2 = 0.1495. The structure analysis of complex 1 shows that the complex consists of two tetrabutylammonium cations and a polyoxomolybdate anion that incorporates two fac-Mn(CO) 3 + units. The anion of complex 1 can be considered as the dimer of two rhomb-like anions by sharing of two corners.