The hydrothermal reaction of a solution of Ni(CH 3 CO 2 ) 2 .4H 2 O, MoO 3 , tetra-4-pyridylpyrazine, H 2 O 3 PCH 3 , and HF at 200 o C for 96 h yields orange crystals of [Ni(tpyrpyz) 2 ] 2 [Mo 4 O 1 2 F 2 ][Mo 6 O 1 7 ].2H 2 O (1.2H 2 O). The structure consists of discrete {Ni(tpyrpyz) 2 } 2 + cations and {Mo 6 O 1 9 } 2 - and {Mo 4 O 1 2 F 2 } 2 - anionic clusters. The hexamolybdate is the well-documented octahedron of octahedra, that is, six {MoO 6 } octahedra in a compact edge-sharing arrangement. The novel oxyfluoride cluster {Mo 4 O 1 2 F 2 } 2 - features two {MoO 4 F 2 } octahedra, sharing the edge defined by the fluoride ligands; the octahedral Mo sites corner-share to two {MoO 4 } tetrahedra in the μ 2 -O, O ' bridging mode.