Si crystallizes in the triclinic P1 space group. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and one Si(7) atom. In the second Si site, Si(2) is bonded to one Si(1), one Si(4), one Si(6), one Si(7), and one Si(8) atom to form distorted SiSi5 trigonal bipyramids that share corners with two equivalent Si(6)Si4 tetrahedra, corners with three equivalent Si(3)Si4 tetrahedra, and  a faceface with one Si(4)Si5 trigonal bipyramid. In the third Si site, Si(3) is bonded to one Si(1), one Si(5), one Si(6), and one Si(7) atom to form corner-sharing SiSi4 tetrahedra. In the fourth Si site, Si(4) is bonded to one Si(1), one Si(2), one Si(5), one Si(6), and one Si(8) atom to form distorted SiSi5 trigonal bipyramids that share corners with two equivalent Si(6)Si4 tetrahedra, corners with three equivalent Si(3)Si4 tetrahedra, and  a faceface with one Si(2)Si5 trigonal bipyramid. In the fifth Si site, Si(5) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(7), and one Si(8) atom. In the sixth Si site, Si(6) is bonded to one Si(2), one Si(3), one Si(4), and one Si(8) atom to form corner-sharing SiSi4 tetrahedra. In the seventh Si site, Si(7) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(5), and one Si(8) atom. In the eighth Si site, Si(8) is bonded in a 5-coordinate geometry to one Si(2), one Si(4), one Si(5), one Si(6), and one Si(7) atom.
Si crystallizes in the triclinic P1 space group. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and one Si(7) atom. The Si(1)-Si(2) bond length is 2.45 Å. The Si(1)-Si(3) bond length is 2.31 Å. The Si(1)-Si(4) bond length is 2.44 Å. The Si(1)-Si(5) bond length is 2.54 Å. The Si(1)-Si(7) bond length is 2.44 Å. In the second Si site, Si(2) is bonded to one Si(1), one Si(4), one Si(6), one Si(7), and one Si(8) atom to form distorted SiSi5 trigonal bipyramids that share corners with two equivalent Si(6)Si4 tetrahedra, corners with three equivalent Si(3)Si4 tetrahedra, and  a faceface with one Si(4)Si5 trigonal bipyramid. The Si(2)-Si(4) bond length is 2.46 Å. The Si(2)-Si(6) bond length is 2.35 Å. The Si(2)-Si(7) bond length is 2.47 Å. The Si(2)-Si(8) bond length is 2.44 Å. In the third Si site, Si(3) is bonded to one Si(1), one Si(5), one Si(6), and one Si(7) atom to form corner-sharing SiSi4 tetrahedra. The Si(3)-Si(5) bond length is 2.34 Å. The Si(3)-Si(6) bond length is 2.34 Å. The Si(3)-Si(7) bond length is 2.35 Å. In the fourth Si site, Si(4) is bonded to one Si(1), one Si(2), one Si(5), one Si(6), and one Si(8) atom to form distorted SiSi5 trigonal bipyramids that share corners with two equivalent Si(6)Si4 tetrahedra, corners with three equivalent Si(3)Si4 tetrahedra, and  a faceface with one Si(2)Si5 trigonal bipyramid. The Si(4)-Si(5) bond length is 2.48 Å. The Si(4)-Si(6) bond length is 2.35 Å. The Si(4)-Si(8) bond length is 2.53 Å. In the fifth Si site, Si(5) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(7), and one Si(8) atom. The Si(5)-Si(7) bond length is 2.55 Å. The Si(5)-Si(8) bond length is 2.48 Å. In the sixth Si site, Si(6) is bonded to one Si(2), one Si(3), one Si(4), and one Si(8) atom to form corner-sharing SiSi4 tetrahedra. The Si(6)-Si(8) bond length is 2.31 Å. In the seventh Si site, Si(7) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(5), and one Si(8) atom. The Si(7)-Si(8) bond length is 2.50 Å. In the eighth Si site, Si(8) is bonded in a 5-coordinate geometry to one Si(2), one Si(4), one Si(5), one Si(6), and one Si(7) atom.