Nb(NiP4)4 crystallizes in the monoclinic C2/c space group. Nb(1) is bonded in a 8-coordinate geometry to two equivalent P(1), two equivalent P(2), two equivalent P(4), and two equivalent P(5) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one P(3), one P(6), two equivalent P(7), and two equivalent P(8) atoms to form NiP6 octahedra that share corners with two equivalent Ni(1)P6 octahedra, corners with four equivalent Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra, corners with two equivalent P(8)Ni2P2 tetrahedra, corners with two equivalent P(7)Ni3P tetrahedra, corners with four equivalent P(2)NbP3 tetrahedra, and  an edgeedge with one Ni(1)P6 octahedra. The corner-sharing octahedral tilt angles range from 57-65°. In the second Ni site, Ni(2) is bonded to one P(1), one P(3), one P(4), one P(5), one P(6), and one P(7) atom to form NiP6 octahedra that share corners with four equivalent Ni(1)P6 octahedra,  a cornercorner with one P(3)Ni2P2 tetrahedra,  a cornercorner with one P(6)Ni2P2 tetrahedra,  a cornercorner with one P(8)Ni2P2 tetrahedra, corners with two equivalent P(4)NbNiP2 tetrahedra, corners with two equivalent P(5)NbNiP2 tetrahedra, and corners with two equivalent P(2)NbP3 tetrahedra. The corner-sharing octahedral tilt angles range from 57-64°. There are eight inequivalent P sites. In the first P site, P(5) is bonded to one Nb(1), one Ni(2), one P(1), and one P(6) atom to form distorted PNbNiP2 tetrahedra that share  a cornercorner with one Ni(1)P6 octahedra, corners with two equivalent Ni(2)P6 octahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra,  a cornercorner with one P(3)Ni2P2 tetrahedra,  a cornercorner with one P(6)Ni2P2 tetrahedra,  a cornercorner with one P(7)Ni3P tetrahedra, corners with two equivalent P(4)NbNiP2 tetrahedra, corners with three equivalent P(2)NbP3 tetrahedra, and  an edgeedge with one P(4)NbNiP2 tetrahedra. The corner-sharing octahedral tilt angles range from 67-74°. In the second P site, P(6) is bonded to one Ni(1), one Ni(2), one P(2), and one P(5) atom to form distorted PNi2P2 tetrahedra that share  a cornercorner with one Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra, corners with three equivalent P(3)Ni2P2 tetrahedra, corners with three equivalent P(8)Ni2P2 tetrahedra, and corners with three equivalent P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles are 71°. In the third P site, P(7) is bonded to one Ni(2), two equivalent Ni(1), and one P(8) atom to form distorted PNi3P tetrahedra that share corners with two equivalent Ni(1)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra,  a cornercorner with one P(2)NbP3 tetrahedra, corners with three equivalent P(3)Ni2P2 tetrahedra, corners with three equivalent P(6)Ni2P2 tetrahedra, corners with four equivalent P(8)Ni2P2 tetrahedra, and  an edgeedge with one P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles range from 73-76°. In the fourth P site, P(8) is bonded to two equivalent Ni(1), one P(2), and one P(7) atom to form distorted PNi2P2 tetrahedra that share  a cornercorner with one Ni(2)P6 octahedra, corners with two equivalent Ni(1)P6 octahedra, corners with two equivalent P(8)Ni2P2 tetrahedra, corners with three equivalent P(3)Ni2P2 tetrahedra, corners with three equivalent P(6)Ni2P2 tetrahedra, and corners with four equivalent P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles range from 70-83°. In the fifth P site, P(1) is bonded in a 4-coordinate geometry to one Nb(1), one Ni(2), one P(4), and one P(5) atom. In the sixth P site, P(2) is bonded to one Nb(1), one P(3), one P(6), and one P(8) atom to form distorted PNbP3 tetrahedra that share corners with two equivalent Ni(2)P6 octahedra, corners with four equivalent Ni(1)P6 octahedra,  a cornercorner with one P(2)NbP3 tetrahedra,  a cornercorner with one P(7)Ni3P tetrahedra, corners with three equivalent P(4)NbNiP2 tetrahedra, and corners with three equivalent P(5)NbNiP2 tetrahedra. The corner-sharing octahedral tilt angles range from 58-76°. In the seventh P site, P(3) is bonded to one Ni(1), one Ni(2), one P(2), and one P(4) atom to form distorted PNi2P2 tetrahedra that share  a cornercorner with one Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra, corners with three equivalent P(6)Ni2P2 tetrahedra, corners with three equivalent P(8)Ni2P2 tetrahedra, and corners with three equivalent P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles are 71°. In the eighth P site, P(4) is bonded to one Nb(1), one Ni(2), one P(1), and one P(3) atom to form distorted PNbNiP2 tetrahedra that share  a cornercorner with one Ni(1)P6 octahedra, corners with two equivalent Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(3)Ni2P2 tetrahedra,  a cornercorner with one P(6)Ni2P2 tetrahedra,  a cornercorner with one P(7)Ni3P tetrahedra, corners with two equivalent P(5)NbNiP2 tetrahedra, corners with three equivalent P(2)NbP3 tetrahedra, and  an edgeedge with one P(5)NbNiP2 tetrahedra. The corner-sharing octahedral tilt angles range from 66-75°.
Nb(NiP4)4 crystallizes in the monoclinic C2/c space group. Nb(1) is bonded in a 8-coordinate geometry to two equivalent P(1), two equivalent P(2), two equivalent P(4), and two equivalent P(5) atoms. Both Nb(1)-P(1) bond lengths are 2.59 Å. Both Nb(1)-P(2) bond lengths are 2.53 Å. Both Nb(1)-P(4) bond lengths are 2.57 Å. Both Nb(1)-P(5) bond lengths are 2.56 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one P(3), one P(6), two equivalent P(7), and two equivalent P(8) atoms to form NiP6 octahedra that share corners with two equivalent Ni(1)P6 octahedra, corners with four equivalent Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra, corners with two equivalent P(8)Ni2P2 tetrahedra, corners with two equivalent P(7)Ni3P tetrahedra, corners with four equivalent P(2)NbP3 tetrahedra, and  an edgeedge with one Ni(1)P6 octahedra. The corner-sharing octahedral tilt angles range from 57-65°. The Ni(1)-P(3) bond length is 2.24 Å. The Ni(1)-P(6) bond length is 2.23 Å. There is one shorter (2.31 Å) and one longer (2.39 Å) Ni(1)-P(7) bond length. There is one shorter (2.31 Å) and one longer (2.37 Å) Ni(1)-P(8) bond length. In the second Ni site, Ni(2) is bonded to one P(1), one P(3), one P(4), one P(5), one P(6), and one P(7) atom to form NiP6 octahedra that share corners with four equivalent Ni(1)P6 octahedra,  a cornercorner with one P(3)Ni2P2 tetrahedra,  a cornercorner with one P(6)Ni2P2 tetrahedra,  a cornercorner with one P(8)Ni2P2 tetrahedra, corners with two equivalent P(4)NbNiP2 tetrahedra, corners with two equivalent P(5)NbNiP2 tetrahedra, and corners with two equivalent P(2)NbP3 tetrahedra. The corner-sharing octahedral tilt angles range from 57-64°. The Ni(2)-P(1) bond length is 2.33 Å. The Ni(2)-P(3) bond length is 2.31 Å. The Ni(2)-P(4) bond length is 2.32 Å. The Ni(2)-P(5) bond length is 2.31 Å. The Ni(2)-P(6) bond length is 2.27 Å. The Ni(2)-P(7) bond length is 2.32 Å. There are eight inequivalent P sites. In the first P site, P(5) is bonded to one Nb(1), one Ni(2), one P(1), and one P(6) atom to form distorted PNbNiP2 tetrahedra that share  a cornercorner with one Ni(1)P6 octahedra, corners with two equivalent Ni(2)P6 octahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra,  a cornercorner with one P(3)Ni2P2 tetrahedra,  a cornercorner with one P(6)Ni2P2 tetrahedra,  a cornercorner with one P(7)Ni3P tetrahedra, corners with two equivalent P(4)NbNiP2 tetrahedra, corners with three equivalent P(2)NbP3 tetrahedra, and  an edgeedge with one P(4)NbNiP2 tetrahedra. The corner-sharing octahedral tilt angles range from 67-74°. The P(5)-P(1) bond length is 2.25 Å. The P(5)-P(6) bond length is 2.24 Å. In the second P site, P(6) is bonded to one Ni(1), one Ni(2), one P(2), and one P(5) atom to form distorted PNi2P2 tetrahedra that share  a cornercorner with one Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra, corners with three equivalent P(3)Ni2P2 tetrahedra, corners with three equivalent P(8)Ni2P2 tetrahedra, and corners with three equivalent P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles are 71°. The P(6)-P(2) bond length is 2.25 Å. In the third P site, P(7) is bonded to one Ni(2), two equivalent Ni(1), and one P(8) atom to form distorted PNi3P tetrahedra that share corners with two equivalent Ni(1)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra,  a cornercorner with one P(2)NbP3 tetrahedra, corners with three equivalent P(3)Ni2P2 tetrahedra, corners with three equivalent P(6)Ni2P2 tetrahedra, corners with four equivalent P(8)Ni2P2 tetrahedra, and  an edgeedge with one P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles range from 73-76°. The P(7)-P(8) bond length is 2.21 Å. In the fourth P site, P(8) is bonded to two equivalent Ni(1), one P(2), and one P(7) atom to form distorted PNi2P2 tetrahedra that share  a cornercorner with one Ni(2)P6 octahedra, corners with two equivalent Ni(1)P6 octahedra, corners with two equivalent P(8)Ni2P2 tetrahedra, corners with three equivalent P(3)Ni2P2 tetrahedra, corners with three equivalent P(6)Ni2P2 tetrahedra, and corners with four equivalent P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles range from 70-83°. The P(8)-P(2) bond length is 2.25 Å. In the fifth P site, P(1) is bonded in a 4-coordinate geometry to one Nb(1), one Ni(2), one P(4), and one P(5) atom. The P(1)-P(4) bond length is 2.25 Å. In the sixth P site, P(2) is bonded to one Nb(1), one P(3), one P(6), and one P(8) atom to form distorted PNbP3 tetrahedra that share corners with two equivalent Ni(2)P6 octahedra, corners with four equivalent Ni(1)P6 octahedra,  a cornercorner with one P(2)NbP3 tetrahedra,  a cornercorner with one P(7)Ni3P tetrahedra, corners with three equivalent P(4)NbNiP2 tetrahedra, and corners with three equivalent P(5)NbNiP2 tetrahedra. The corner-sharing octahedral tilt angles range from 58-76°. The P(2)-P(3) bond length is 2.25 Å. In the seventh P site, P(3) is bonded to one Ni(1), one Ni(2), one P(2), and one P(4) atom to form distorted PNi2P2 tetrahedra that share  a cornercorner with one Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(5)NbNiP2 tetrahedra, corners with three equivalent P(6)Ni2P2 tetrahedra, corners with three equivalent P(8)Ni2P2 tetrahedra, and corners with three equivalent P(7)Ni3P tetrahedra. The corner-sharing octahedral tilt angles are 71°. The P(3)-P(4) bond length is 2.24 Å. In the eighth P site, P(4) is bonded to one Nb(1), one Ni(2), one P(1), and one P(3) atom to form distorted PNbNiP2 tetrahedra that share  a cornercorner with one Ni(1)P6 octahedra, corners with two equivalent Ni(2)P6 octahedra,  a cornercorner with one P(4)NbNiP2 tetrahedra,  a cornercorner with one P(3)Ni2P2 tetrahedra,  a cornercorner with one P(6)Ni2P2 tetrahedra,  a cornercorner with one P(7)Ni3P tetrahedra, corners with two equivalent P(5)NbNiP2 tetrahedra, corners with three equivalent P(2)NbP3 tetrahedra, and  an edgeedge with one P(5)NbNiP2 tetrahedra. The corner-sharing octahedral tilt angles range from 66-75°.