Nb7P4 crystallizes in the monoclinic C2/m space group. There are eight inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 4-coordinate geometry to two equivalent P(1) and three equivalent P(4) atoms. In the second Nb site, Nb(2) is bonded to one P(1), two equivalent P(2), and two equivalent P(3) atoms to form a mixture of distorted edge, corner, and face-sharing NbP5 trigonal bipyramids. In the third Nb site, Nb(3) is bonded in a 5-coordinate geometry to two equivalent P(2) and three equivalent P(3) atoms. In the fourth Nb site, Nb(4) is bonded to one P(1), two equivalent P(2), and two equivalent P(4) atoms to form a mixture of distorted edge, corner, and face-sharing NbP5 trigonal bipyramids. In the fifth Nb site, Nb(5) is bonded in a 4-coordinate geometry to one P(2), one P(4), and two equivalent P(3) atoms. In the sixth Nb site, Nb(6) is bonded in a 4-coordinate geometry to one P(3), two equivalent P(1), and two equivalent P(4) atoms. In the seventh Nb site, Nb(7) is bonded in a square co-planar geometry to two equivalent P(2) and two equivalent P(3) atoms. In the eighth Nb site, Nb(8) is bonded in a distorted square co-planar geometry to two equivalent P(1) and two equivalent P(4) atoms. There are four inequivalent P sites. In the first P site, P(3) is bonded in a 9-coordinate geometry to one Nb(6), one Nb(7), two equivalent Nb(2), two equivalent Nb(5), and three equivalent Nb(3) atoms. In the second P site, P(4) is bonded in a 9-coordinate geometry to one Nb(5), one Nb(8), two equivalent Nb(4), two equivalent Nb(6), and three equivalent Nb(1) atoms. In the third P site, P(1) is bonded to one Nb(2), one Nb(4), one Nb(8), two equivalent Nb(1), and two equivalent Nb(6) atoms to form a mixture of distorted edge and corner-sharing PNb7 pentagonal bipyramids. In the fourth P site, P(2) is bonded in a 8-coordinate geometry to one Nb(5), one Nb(7), two equivalent Nb(2), two equivalent Nb(3), and two equivalent Nb(4) atoms.
Nb7P4 crystallizes in the monoclinic C2/m space group. There are eight inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 4-coordinate geometry to two equivalent P(1) and three equivalent P(4) atoms. Both Nb(1)-P(1) bond lengths are 2.61 Å. There are two shorter (2.58 Å) and one longer (2.99 Å) Nb(1)-P(4) bond length. In the second Nb site, Nb(2) is bonded to one P(1), two equivalent P(2), and two equivalent P(3) atoms to form a mixture of distorted edge, corner, and face-sharing NbP5 trigonal bipyramids. The Nb(2)-P(1) bond length is 2.49 Å. Both Nb(2)-P(2) bond lengths are 2.58 Å. Both Nb(2)-P(3) bond lengths are 2.59 Å. In the third Nb site, Nb(3) is bonded in a 5-coordinate geometry to two equivalent P(2) and three equivalent P(3) atoms. Both Nb(3)-P(2) bond lengths are 2.64 Å. There are two shorter (2.60 Å) and one longer (2.90 Å) Nb(3)-P(3) bond length. In the fourth Nb site, Nb(4) is bonded to one P(1), two equivalent P(2), and two equivalent P(4) atoms to form a mixture of distorted edge, corner, and face-sharing NbP5 trigonal bipyramids. The Nb(4)-P(1) bond length is 2.46 Å. Both Nb(4)-P(2) bond lengths are 2.62 Å. Both Nb(4)-P(4) bond lengths are 2.54 Å. In the fifth Nb site, Nb(5) is bonded in a 4-coordinate geometry to one P(2), one P(4), and two equivalent P(3) atoms. The Nb(5)-P(2) bond length is 2.56 Å. The Nb(5)-P(4) bond length is 2.72 Å. Both Nb(5)-P(3) bond lengths are 2.48 Å. In the sixth Nb site, Nb(6) is bonded in a 4-coordinate geometry to one P(3), two equivalent P(1), and two equivalent P(4) atoms. The Nb(6)-P(3) bond length is 3.04 Å. Both Nb(6)-P(1) bond lengths are 2.60 Å. Both Nb(6)-P(4) bond lengths are 2.63 Å. In the seventh Nb site, Nb(7) is bonded in a square co-planar geometry to two equivalent P(2) and two equivalent P(3) atoms. Both Nb(7)-P(2) bond lengths are 2.61 Å. Both Nb(7)-P(3) bond lengths are 2.65 Å. In the eighth Nb site, Nb(8) is bonded in a distorted square co-planar geometry to two equivalent P(1) and two equivalent P(4) atoms. Both Nb(8)-P(1) bond lengths are 2.52 Å. Both Nb(8)-P(4) bond lengths are 2.69 Å. There are four inequivalent P sites. In the first P site, P(3) is bonded in a 9-coordinate geometry to one Nb(6), one Nb(7), two equivalent Nb(2), two equivalent Nb(5), and three equivalent Nb(3) atoms. In the second P site, P(4) is bonded in a 9-coordinate geometry to one Nb(5), one Nb(8), two equivalent Nb(4), two equivalent Nb(6), and three equivalent Nb(1) atoms. In the third P site, P(1) is bonded to one Nb(2), one Nb(4), one Nb(8), two equivalent Nb(1), and two equivalent Nb(6) atoms to form a mixture of distorted edge and corner-sharing PNb7 pentagonal bipyramids. In the fourth P site, P(2) is bonded in a 8-coordinate geometry to one Nb(5), one Nb(7), two equivalent Nb(2), two equivalent Nb(3), and two equivalent Nb(4) atoms.