PrSiP3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one P(6), two equivalent P(1), two equivalent P(2), two equivalent P(3), and two equivalent P(4) atoms. In the second Pr site, Pr(2) is bonded in a 9-coordinate geometry to one P(5), two equivalent P(1), two equivalent P(2), two equivalent P(3), and two equivalent P(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one P(4), one P(6), and two equivalent P(5) atoms to form corner-sharing SiP4 tetrahedra. In the second Si site, Si(2) is bonded to one P(3), one P(5), and two equivalent P(6) atoms to form corner-sharing SiP4 tetrahedra. There are six inequivalent P sites. In the first P site, P(5) is bonded to one Pr(2), one Si(2), and two equivalent Si(1) atoms to form distorted PPrSi3 tetrahedra that share corners with two equivalent P(5)PrSi3 tetrahedra, corners with four equivalent P(6)PrSi3 tetrahedra,  a cornercorner with one P(3)Pr4Si trigonal bipyramid, corners with two equivalent P(4)Pr4Si trigonal bipyramids,  an edgeedge with one P(3)Pr4Si trigonal bipyramid, and  an edgeedge with one P(4)Pr4Si trigonal bipyramid. In the second P site, P(6) is bonded to one Pr(1), one Si(1), and two equivalent Si(2) atoms to form distorted PPrSi3 tetrahedra that share corners with two equivalent P(6)PrSi3 tetrahedra, corners with four equivalent P(5)PrSi3 tetrahedra,  a cornercorner with one P(4)Pr4Si trigonal bipyramid, corners with two equivalent P(3)Pr4Si trigonal bipyramids,  an edgeedge with one P(3)Pr4Si trigonal bipyramid, and  an edgeedge with one P(4)Pr4Si trigonal bipyramid. In the third P site, P(1) is bonded in a 6-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), and two equivalent P(2) atoms. In the fourth P site, P(2) is bonded in a 6-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), and two equivalent P(1) atoms. In the fifth P site, P(3) is bonded to two equivalent Pr(1), two equivalent Pr(2), and one Si(2) atom to form distorted PPr4Si trigonal bipyramids that share  a cornercorner with one P(5)PrSi3 tetrahedra, corners with two equivalent P(6)PrSi3 tetrahedra, corners with four equivalent P(3)Pr4Si trigonal bipyramids,  an edgeedge with one P(5)PrSi3 tetrahedra,  an edgeedge with one P(6)PrSi3 tetrahedra, and edges with four equivalent P(4)Pr4Si trigonal bipyramids. In the sixth P site, P(4) is bonded to two equivalent Pr(1), two equivalent Pr(2), and one Si(1) atom to form distorted PPr4Si trigonal bipyramids that share  a cornercorner with one P(6)PrSi3 tetrahedra, corners with two equivalent P(5)PrSi3 tetrahedra, corners with four equivalent P(4)Pr4Si trigonal bipyramids,  an edgeedge with one P(5)PrSi3 tetrahedra,  an edgeedge with one P(6)PrSi3 tetrahedra, and edges with four equivalent P(3)Pr4Si trigonal bipyramids.
PrSiP3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one P(6), two equivalent P(1), two equivalent P(2), two equivalent P(3), and two equivalent P(4) atoms. The Pr(1)-P(6) bond length is 3.12 Å. There is one shorter (3.30 Å) and one longer (3.32 Å) Pr(1)-P(1) bond length. There is one shorter (3.30 Å) and one longer (3.31 Å) Pr(1)-P(2) bond length. There is one shorter (3.07 Å) and one longer (3.15 Å) Pr(1)-P(3) bond length. There is one shorter (2.98 Å) and one longer (3.01 Å) Pr(1)-P(4) bond length. In the second Pr site, Pr(2) is bonded in a 9-coordinate geometry to one P(5), two equivalent P(1), two equivalent P(2), two equivalent P(3), and two equivalent P(4) atoms. The Pr(2)-P(5) bond length is 3.03 Å. There is one shorter (2.97 Å) and one longer (3.23 Å) Pr(2)-P(1) bond length. There is one shorter (2.97 Å) and one longer (3.25 Å) Pr(2)-P(2) bond length. There is one shorter (2.95 Å) and one longer (2.98 Å) Pr(2)-P(3) bond length. There is one shorter (3.00 Å) and one longer (3.05 Å) Pr(2)-P(4) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one P(4), one P(6), and two equivalent P(5) atoms to form corner-sharing SiP4 tetrahedra. The Si(1)-P(4) bond length is 2.19 Å. The Si(1)-P(6) bond length is 2.24 Å. There is one shorter (2.22 Å) and one longer (2.24 Å) Si(1)-P(5) bond length. In the second Si site, Si(2) is bonded to one P(3), one P(5), and two equivalent P(6) atoms to form corner-sharing SiP4 tetrahedra. The Si(2)-P(3) bond length is 2.19 Å. The Si(2)-P(5) bond length is 2.25 Å. There is one shorter (2.22 Å) and one longer (2.26 Å) Si(2)-P(6) bond length. There are six inequivalent P sites. In the first P site, P(5) is bonded to one Pr(2), one Si(2), and two equivalent Si(1) atoms to form distorted PPrSi3 tetrahedra that share corners with two equivalent P(5)PrSi3 tetrahedra, corners with four equivalent P(6)PrSi3 tetrahedra,  a cornercorner with one P(3)Pr4Si trigonal bipyramid, corners with two equivalent P(4)Pr4Si trigonal bipyramids,  an edgeedge with one P(3)Pr4Si trigonal bipyramid, and  an edgeedge with one P(4)Pr4Si trigonal bipyramid. In the second P site, P(6) is bonded to one Pr(1), one Si(1), and two equivalent Si(2) atoms to form distorted PPrSi3 tetrahedra that share corners with two equivalent P(6)PrSi3 tetrahedra, corners with four equivalent P(5)PrSi3 tetrahedra,  a cornercorner with one P(4)Pr4Si trigonal bipyramid, corners with two equivalent P(3)Pr4Si trigonal bipyramids,  an edgeedge with one P(3)Pr4Si trigonal bipyramid, and  an edgeedge with one P(4)Pr4Si trigonal bipyramid. In the third P site, P(1) is bonded in a 6-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), and two equivalent P(2) atoms. There is one shorter (2.25 Å) and one longer (2.27 Å) P(1)-P(2) bond length. In the fourth P site, P(2) is bonded in a 6-coordinate geometry to two equivalent Pr(1), two equivalent Pr(2), and two equivalent P(1) atoms. In the fifth P site, P(3) is bonded to two equivalent Pr(1), two equivalent Pr(2), and one Si(2) atom to form distorted PPr4Si trigonal bipyramids that share  a cornercorner with one P(5)PrSi3 tetrahedra, corners with two equivalent P(6)PrSi3 tetrahedra, corners with four equivalent P(3)Pr4Si trigonal bipyramids,  an edgeedge with one P(5)PrSi3 tetrahedra,  an edgeedge with one P(6)PrSi3 tetrahedra, and edges with four equivalent P(4)Pr4Si trigonal bipyramids. In the sixth P site, P(4) is bonded to two equivalent Pr(1), two equivalent Pr(2), and one Si(1) atom to form distorted PPr4Si trigonal bipyramids that share  a cornercorner with one P(6)PrSi3 tetrahedra, corners with two equivalent P(5)PrSi3 tetrahedra, corners with four equivalent P(4)Pr4Si trigonal bipyramids,  an edgeedge with one P(5)PrSi3 tetrahedra,  an edgeedge with one P(6)PrSi3 tetrahedra, and edges with four equivalent P(3)Pr4Si trigonal bipyramids.