Pr2Ni7P4 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 16-coordinate geometry to one Ni(3), one Ni(4), two equivalent Ni(2), two equivalent Ni(6), two equivalent Ni(7), three equivalent Ni(1), two equivalent P(4), and three equivalent P(1) atoms. In the second Pr site, Pr(2) is bonded in a 17-coordinate geometry to one Ni(3), one Ni(6), one Ni(7), two equivalent Ni(2), three equivalent Ni(4), three equivalent Ni(5), two equivalent P(2), two equivalent P(3), and two equivalent P(4) atoms. There are seven inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Pr(1), one P(2), and two equivalent P(1) atoms. In the second Ni site, Ni(2) is bonded in a 4-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), one P(3), one P(4), and two equivalent P(1) atoms. In the third Ni site, Ni(3) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), one P(3), and two equivalent P(2) atoms. In the fourth Ni site, Ni(4) is bonded to one Pr(1), three equivalent Pr(2), one P(2), one P(3), and two equivalent P(4) atoms to form a mixture of distorted edge and corner-sharing NiPr4P4 tetrahedra. In the fifth Ni site, Ni(5) is bonded in a 4-coordinate geometry to three equivalent Pr(2), one P(2), one P(4), and two equivalent P(3) atoms. In the sixth Ni site, Ni(6) is bonded in a 4-coordinate geometry to one Pr(2), two equivalent Pr(1), one P(1), one P(4), and two equivalent P(2) atoms. In the seventh Ni site, Ni(7) is bonded in a distorted trigonal non-coplanar geometry to one Pr(2), two equivalent Pr(1), one P(1), and two equivalent P(3) atoms. There are four inequivalent P sites. In the first P site, P(1) is bonded in a 9-coordinate geometry to three equivalent Pr(1), one Ni(6), one Ni(7), two equivalent Ni(1), and two equivalent Ni(2) atoms. In the second P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Pr(2), one Ni(1), one Ni(4), one Ni(5), two equivalent Ni(3), and two equivalent Ni(6) atoms. In the third P site, P(3) is bonded in a 9-coordinate geometry to two equivalent Pr(2), one Ni(2), one Ni(3), one Ni(4), two equivalent Ni(5), and two equivalent Ni(7) atoms. In the fourth P site, P(4) is bonded in a 9-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), one Ni(2), one Ni(5), one Ni(6), and two equivalent Ni(4) atoms.
Pr2Ni7P4 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 16-coordinate geometry to one Ni(3), one Ni(4), two equivalent Ni(2), two equivalent Ni(6), two equivalent Ni(7), three equivalent Ni(1), two equivalent P(4), and three equivalent P(1) atoms. The Pr(1)-Ni(3) bond length is 3.05 Å. The Pr(1)-Ni(4) bond length is 3.28 Å. Both Pr(1)-Ni(2) bond lengths are 3.33 Å. Both Pr(1)-Ni(6) bond lengths are 3.01 Å. Both Pr(1)-Ni(7) bond lengths are 3.14 Å. There are two shorter (3.10 Å) and one longer (3.19 Å) Pr(1)-Ni(1) bond length. Both Pr(1)-P(4) bond lengths are 3.02 Å. There is one shorter (2.98 Å) and two longer (3.07 Å) Pr(1)-P(1) bond lengths. In the second Pr site, Pr(2) is bonded in a 17-coordinate geometry to one Ni(3), one Ni(6), one Ni(7), two equivalent Ni(2), three equivalent Ni(4), three equivalent Ni(5), two equivalent P(2), two equivalent P(3), and two equivalent P(4) atoms. The Pr(2)-Ni(3) bond length is 3.16 Å. The Pr(2)-Ni(6) bond length is 3.32 Å. The Pr(2)-Ni(7) bond length is 3.15 Å. Both Pr(2)-Ni(2) bond lengths are 3.05 Å. There are two shorter (3.16 Å) and one longer (3.19 Å) Pr(2)-Ni(4) bond length. There are two shorter (3.01 Å) and one longer (3.18 Å) Pr(2)-Ni(5) bond length. Both Pr(2)-P(2) bond lengths are 2.95 Å. Both Pr(2)-P(3) bond lengths are 2.92 Å. Both Pr(2)-P(4) bond lengths are 2.97 Å. There are seven inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Pr(1), one P(2), and two equivalent P(1) atoms. The Ni(1)-P(2) bond length is 2.16 Å. Both Ni(1)-P(1) bond lengths are 2.31 Å. In the second Ni site, Ni(2) is bonded in a 4-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), one P(3), one P(4), and two equivalent P(1) atoms. The Ni(2)-P(3) bond length is 2.33 Å. The Ni(2)-P(4) bond length is 2.54 Å. Both Ni(2)-P(1) bond lengths are 2.43 Å. In the third Ni site, Ni(3) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), one P(3), and two equivalent P(2) atoms. The Ni(3)-P(3) bond length is 2.15 Å. Both Ni(3)-P(2) bond lengths are 2.32 Å. In the fourth Ni site, Ni(4) is bonded to one Pr(1), three equivalent Pr(2), one P(2), one P(3), and two equivalent P(4) atoms to form a mixture of distorted edge and corner-sharing NiPr4P4 tetrahedra. The Ni(4)-P(2) bond length is 2.27 Å. The Ni(4)-P(3) bond length is 2.35 Å. Both Ni(4)-P(4) bond lengths are 2.38 Å. In the fifth Ni site, Ni(5) is bonded in a 4-coordinate geometry to three equivalent Pr(2), one P(2), one P(4), and two equivalent P(3) atoms. The Ni(5)-P(2) bond length is 2.31 Å. The Ni(5)-P(4) bond length is 2.28 Å. Both Ni(5)-P(3) bond lengths are 2.38 Å. In the sixth Ni site, Ni(6) is bonded in a 4-coordinate geometry to one Pr(2), two equivalent Pr(1), one P(1), one P(4), and two equivalent P(2) atoms. The Ni(6)-P(1) bond length is 2.36 Å. The Ni(6)-P(4) bond length is 2.25 Å. Both Ni(6)-P(2) bond lengths are 2.40 Å. In the seventh Ni site, Ni(7) is bonded in a distorted trigonal non-coplanar geometry to one Pr(2), two equivalent Pr(1), one P(1), and two equivalent P(3) atoms. The Ni(7)-P(1) bond length is 2.18 Å. Both Ni(7)-P(3) bond lengths are 2.33 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded in a 9-coordinate geometry to three equivalent Pr(1), one Ni(6), one Ni(7), two equivalent Ni(1), and two equivalent Ni(2) atoms. In the second P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Pr(2), one Ni(1), one Ni(4), one Ni(5), two equivalent Ni(3), and two equivalent Ni(6) atoms. In the third P site, P(3) is bonded in a 9-coordinate geometry to two equivalent Pr(2), one Ni(2), one Ni(3), one Ni(4), two equivalent Ni(5), and two equivalent Ni(7) atoms. In the fourth P site, P(4) is bonded in a 9-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), one Ni(2), one Ni(5), one Ni(6), and two equivalent Ni(4) atoms.