Ba3(Si2P3)2 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to four equivalent P(1) and four equivalent P(4) atoms. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one P(2), two equivalent P(1), two equivalent P(4), and three equivalent P(3) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one P(3), two equivalent P(1), two equivalent P(4), and three equivalent P(2) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to two equivalent Si(1), one P(1), and one P(4) atom. In the second Si site, Si(2) is bonded to one P(2), one P(3), and two equivalent P(4) atoms to form corner-sharing SiP4 tetrahedra. In the third Si site, Si(3) is bonded to one P(2), one P(3), and two equivalent P(1) atoms to form corner-sharing SiP4 tetrahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Si(1), and one Si(3) atom. In the second P site, P(2) is bonded in a 6-coordinate geometry to one Ba(2), three equivalent Ba(3), one Si(2), and one Si(3) atom. In the third P site, P(3) is bonded in a 6-coordinate geometry to one Ba(3), three equivalent Ba(2), one Si(2), and one Si(3) atom. In the fourth P site, P(4) is bonded to one Ba(2), one Ba(3), two equivalent Ba(1), one Si(1), and one Si(2) atom to form a mixture of distorted edge, corner, and face-sharing PBa4Si2 octahedra. The corner-sharing octahedral tilt angles are 2°.
Ba3(Si2P3)2 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to four equivalent P(1) and four equivalent P(4) atoms. There are two shorter (3.30 Å) and two longer (3.42 Å) Ba(1)-P(1) bond lengths. There are two shorter (3.30 Å) and two longer (3.42 Å) Ba(1)-P(4) bond lengths. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one P(2), two equivalent P(1), two equivalent P(4), and three equivalent P(3) atoms. The Ba(2)-P(2) bond length is 3.30 Å. Both Ba(2)-P(1) bond lengths are 3.30 Å. Both Ba(2)-P(4) bond lengths are 3.30 Å. There is one shorter (3.29 Å) and two longer (3.74 Å) Ba(2)-P(3) bond lengths. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one P(3), two equivalent P(1), two equivalent P(4), and three equivalent P(2) atoms. The Ba(3)-P(3) bond length is 3.19 Å. Both Ba(3)-P(1) bond lengths are 3.36 Å. Both Ba(3)-P(4) bond lengths are 3.37 Å. There is one shorter (3.21 Å) and two longer (3.72 Å) Ba(3)-P(2) bond lengths. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to two equivalent Si(1), one P(1), and one P(4) atom. There is one shorter (2.37 Å) and one longer (2.52 Å) Si(1)-Si(1) bond length. The Si(1)-P(1) bond length is 2.24 Å. The Si(1)-P(4) bond length is 2.24 Å. In the second Si site, Si(2) is bonded to one P(2), one P(3), and two equivalent P(4) atoms to form corner-sharing SiP4 tetrahedra. The Si(2)-P(2) bond length is 2.30 Å. The Si(2)-P(3) bond length is 2.32 Å. Both Si(2)-P(4) bond lengths are 2.24 Å. In the third Si site, Si(3) is bonded to one P(2), one P(3), and two equivalent P(1) atoms to form corner-sharing SiP4 tetrahedra. The Si(3)-P(2) bond length is 2.29 Å. The Si(3)-P(3) bond length is 2.32 Å. Both Si(3)-P(1) bond lengths are 2.24 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Si(1), and one Si(3) atom. In the second P site, P(2) is bonded in a 6-coordinate geometry to one Ba(2), three equivalent Ba(3), one Si(2), and one Si(3) atom. In the third P site, P(3) is bonded in a 6-coordinate geometry to one Ba(3), three equivalent Ba(2), one Si(2), and one Si(3) atom. In the fourth P site, P(4) is bonded to one Ba(2), one Ba(3), two equivalent Ba(1), one Si(1), and one Si(2) atom to form a mixture of distorted edge, corner, and face-sharing PBa4Si2 octahedra. The corner-sharing octahedral tilt angles are 2°.