Pr3NiSi3 crystallizes in the orthorhombic Imm2 space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to four equivalent Ni(1), two equivalent Si(1), two equivalent Si(2), and four equivalent Si(3) atoms to form a mixture of face and edge-sharing PrSi8Ni4 cuboctahedra. In the second Pr site, Pr(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the third Pr site, Pr(3) is bonded in a 7-coordinate geometry to two equivalent Ni(1), one Si(2), and four equivalent Si(1) atoms. Ni(1) is bonded in a 9-coordinate geometry to two equivalent Pr(3), four equivalent Pr(1), one Si(3), and two equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Pr(2), two equivalent Pr(1), four equivalent Pr(3), and two equivalent Ni(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Pr(3), two equivalent Pr(1), four equivalent Pr(2), and two equivalent Si(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Pr(2), four equivalent Pr(1), one Ni(1), and two equivalent Si(2) atoms.
Pr3NiSi3 crystallizes in the orthorhombic Imm2 space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to four equivalent Ni(1), two equivalent Si(1), two equivalent Si(2), and four equivalent Si(3) atoms to form a mixture of face and edge-sharing PrSi8Ni4 cuboctahedra. All Pr(1)-Ni(1) bond lengths are 3.19 Å. Both Pr(1)-Si(1) bond lengths are 3.24 Å. Both Pr(1)-Si(2) bond lengths are 3.32 Å. All Pr(1)-Si(3) bond lengths are 3.14 Å. In the second Pr site, Pr(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. The Pr(2)-Si(1) bond length is 3.30 Å. Both Pr(2)-Si(3) bond lengths are 3.15 Å. All Pr(2)-Si(2) bond lengths are 3.07 Å. In the third Pr site, Pr(3) is bonded in a 7-coordinate geometry to two equivalent Ni(1), one Si(2), and four equivalent Si(1) atoms. Both Pr(3)-Ni(1) bond lengths are 3.01 Å. The Pr(3)-Si(2) bond length is 3.26 Å. All Pr(3)-Si(1) bond lengths are 3.08 Å. Ni(1) is bonded in a 9-coordinate geometry to two equivalent Pr(3), four equivalent Pr(1), one Si(3), and two equivalent Si(1) atoms. The Ni(1)-Si(3) bond length is 2.27 Å. Both Ni(1)-Si(1) bond lengths are 2.34 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Pr(2), two equivalent Pr(1), four equivalent Pr(3), and two equivalent Ni(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Pr(3), two equivalent Pr(1), four equivalent Pr(2), and two equivalent Si(3) atoms. Both Si(2)-Si(3) bond lengths are 2.48 Å. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Pr(2), four equivalent Pr(1), one Ni(1), and two equivalent Si(2) atoms.