YSi2 crystallizes in the monoclinic Pm space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 6-coordinate geometry to two equivalent Si(3), two equivalent Si(6), and two equivalent Si(8) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(4), two equivalent Si(7), and two equivalent Si(8) atoms. In the third Y site, Y(3) is bonded in a 6-coordinate geometry to two equivalent Si(2), two equivalent Si(4), two equivalent Si(5), and two equivalent Si(8) atoms. In the fourth Y site, Y(4) is bonded in a 10-coordinate geometry to two equivalent Si(1), two equivalent Si(2), two equivalent Si(3), two equivalent Si(4), two equivalent Si(5), and two equivalent Si(6) atoms. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to two equivalent Y(2), two equivalent Y(4), one Si(5), one Si(6), and one Si(8) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to two equivalent Y(3), two equivalent Y(4), one Si(4), one Si(6), and one Si(7) atom. In the third Si site, Si(3) is bonded to two equivalent Y(1), two equivalent Y(4), one Si(4), and one Si(5) atom to form distorted edge-sharing SiY4Si2 octahedra. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Y(2), two equivalent Y(3), two equivalent Y(4), one Si(2), one Si(3), and one Si(8) atom. In the fifth Si site, Si(5) is bonded in a 6-coordinate geometry to two equivalent Y(3), two equivalent Y(4), one Si(1), and one Si(3) atom. In the sixth Si site, Si(6) is bonded in a 7-coordinate geometry to two equivalent Y(1), two equivalent Y(4), one Si(1), one Si(2), and one Si(7) atom. In the seventh Si site, Si(7) is bonded in a 2-coordinate geometry to two equivalent Y(2), one Si(2), and one Si(6) atom. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to two equivalent Y(1), two equivalent Y(2), two equivalent Y(3), one Si(1), and one Si(4) atom.
YSi2 crystallizes in the monoclinic Pm space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 6-coordinate geometry to two equivalent Si(3), two equivalent Si(6), and two equivalent Si(8) atoms. Both Y(1)-Si(3) bond lengths are 2.91 Å. Both Y(1)-Si(6) bond lengths are 2.83 Å. Both Y(1)-Si(8) bond lengths are 3.04 Å. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(4), two equivalent Si(7), and two equivalent Si(8) atoms. Both Y(2)-Si(1) bond lengths are 2.89 Å. Both Y(2)-Si(4) bond lengths are 2.98 Å. Both Y(2)-Si(7) bond lengths are 2.96 Å. Both Y(2)-Si(8) bond lengths are 3.22 Å. In the third Y site, Y(3) is bonded in a 6-coordinate geometry to two equivalent Si(2), two equivalent Si(4), two equivalent Si(5), and two equivalent Si(8) atoms. Both Y(3)-Si(2) bond lengths are 2.85 Å. Both Y(3)-Si(4) bond lengths are 3.30 Å. Both Y(3)-Si(5) bond lengths are 2.95 Å. Both Y(3)-Si(8) bond lengths are 2.97 Å. In the fourth Y site, Y(4) is bonded in a 10-coordinate geometry to two equivalent Si(1), two equivalent Si(2), two equivalent Si(3), two equivalent Si(4), two equivalent Si(5), and two equivalent Si(6) atoms. Both Y(4)-Si(1) bond lengths are 3.16 Å. Both Y(4)-Si(2) bond lengths are 3.08 Å. Both Y(4)-Si(3) bond lengths are 3.00 Å. Both Y(4)-Si(4) bond lengths are 3.56 Å. Both Y(4)-Si(5) bond lengths are 3.09 Å. Both Y(4)-Si(6) bond lengths are 3.05 Å. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to two equivalent Y(2), two equivalent Y(4), one Si(5), one Si(6), and one Si(8) atom. The Si(1)-Si(5) bond length is 2.40 Å. The Si(1)-Si(6) bond length is 2.30 Å. The Si(1)-Si(8) bond length is 2.54 Å. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to two equivalent Y(3), two equivalent Y(4), one Si(4), one Si(6), and one Si(7) atom. The Si(2)-Si(4) bond length is 2.30 Å. The Si(2)-Si(6) bond length is 2.24 Å. The Si(2)-Si(7) bond length is 2.45 Å. In the third Si site, Si(3) is bonded to two equivalent Y(1), two equivalent Y(4), one Si(4), and one Si(5) atom to form distorted edge-sharing SiY4Si2 octahedra. The Si(3)-Si(4) bond length is 2.50 Å. The Si(3)-Si(5) bond length is 2.48 Å. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Y(2), two equivalent Y(3), two equivalent Y(4), one Si(2), one Si(3), and one Si(8) atom. The Si(4)-Si(8) bond length is 2.61 Å. In the fifth Si site, Si(5) is bonded in a 6-coordinate geometry to two equivalent Y(3), two equivalent Y(4), one Si(1), and one Si(3) atom. In the sixth Si site, Si(6) is bonded in a 7-coordinate geometry to two equivalent Y(1), two equivalent Y(4), one Si(1), one Si(2), and one Si(7) atom. The Si(6)-Si(7) bond length is 2.51 Å. In the seventh Si site, Si(7) is bonded in a 2-coordinate geometry to two equivalent Y(2), one Si(2), and one Si(6) atom. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to two equivalent Y(1), two equivalent Y(2), two equivalent Y(3), one Si(1), and one Si(4) atom.