Our continuing study of sulfur-bridged cubane-type mixed-metal cluster containing cubane-type Mo 3 FeS 4 core has led to the preparation of a new molybdenum-iron cluster [Mo 3 FeS 4 (nta)Cl(H 2 O) 6 ] 5H 2 O (A) where nta = nitrilotriacetate. Structural investigation of the cluster has revealed that only one molybdenum atom is coordinated with nitorilotriacetate ligand, while the other two are coordinated with water molecules. The ortep drawing of [Mo 3 FeS 4 (nta)Cl(H 2 O) 6 ] in A is shown in Figure 1. Compound A crystallizes in monoclinic space group C2/m with a = 23.899 (5) 9, b = 9.748 (2) 9, c = 12.014 (2) 9, β = 103.11 (2) °, V = 2726.1 (9) 9, Z = 4, R = 5.95%. The iron atom is tetrahedrally coordinated with three S from the core and Cl atoms. One uncoordinated CO 2 group in the nta ligand has two similar C - O distances, indicating the existence of -COO 2 - in the ligand.X-ray photoelectron spectrum of A is compared with that of [Mo 3 FeS 4 (H 2 O) 1 0 ](CH 3 C 6 H 4 SO 3 ) 4 7H 2 O (B). The Mo-3d 5 2 and Mo-3d 3 2 binding energies of A and B are listed on Table 1. Because of coordination of negative ion, the binding energies of A become smaller than those of B. Molybdenum-iron clusters with Mo 3 FeS 4 cores having two or three nta ligands are under investigation.