A reinvestigation of the ternary system Mo+Ni+P has been established using X-ray di4raction, scanning electron microscopy, and electron probe microanalysis. This up-to-date system shows 10 ternary phosphides, which were mostly structurally characterized from X-ray powder or single-crystal data. Among these phosphides, three new ternary phases are reported for the 5rst time: triclinic Mo 8.58 Ni 7.42 P 6 (a ؍ 7.0079(4) A > , b ؍ 7.0290(4) A > , c ؍ 7.0308(4) A > , ؍ 68.893(3)3, ؍ 73.196(3)3, ؍ 60.149(3)3, space group P1 , new structure type), cubic Mo 3 Ni 2 P 1.18 (a ؍ 10.846(2) A > , space group F4 3m, Mn 3 Ni 2 Sitype structure), and tetragonal Mo 2.675 Ni 0.325 P (a ؍ 9.733(1) A > , b ؍ 4.7805(7) A > , space group I4 , Mo 3 P-type derivative structure). These phases were prepared from the elements by hightemperature annealing at 13503C, and their crystal structures exhibit numerous strong metal+metal bonds in agreement with their metal-to-nonmetal ratio higher than 2.5. Indeed, in a general way, the phosphorus coordination number for Mo and Ni atoms is relatively small so that metallic arrangements as [Ni 4 ] tetrahedra and [Mo 6 ] octahedra can be considered as examples in the structures of Mo 8.