Gd3SiBr3 crystallizes in the monoclinic C2 space group. There are seven inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one Si(1), one Si(3), one Br(1), one Br(3), one Br(4), and one Br(7) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the second Gd site, Gd(2) is bonded to one Si(1), one Si(2), one Br(2), one Br(4), one Br(6), and one Br(7) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. In the third Gd site, Gd(3) is bonded to one Si(1), one Si(2), one Br(1), one Br(3), one Br(4), and one Br(5) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. In the fourth Gd site, Gd(4) is bonded to two equivalent Si(1), two equivalent Br(1), and two equivalent Br(2) atoms to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the fifth Gd site, Gd(5) is bonded to one Si(2), one Si(3), one Br(1), one Br(2), one Br(3), and one Br(6) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the sixth Gd site, Gd(6) is bonded to one Si(1), one Si(3), one Br(2), one Br(4), one Br(5), and one Br(6) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. In the seventh Gd site, Gd(7) is bonded to two equivalent Si(1), two equivalent Br(3), and two equivalent Br(6) atoms to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one Gd(1), one Gd(2), one Gd(3), one Gd(4), one Gd(6), and one Gd(7) atom to form edge-sharing SiGd6 octahedra. In the second Si site, Si(2) is bonded to two equivalent Gd(2), two equivalent Gd(3), and two equivalent Gd(5) atoms to form edge-sharing SiGd6 octahedra. In the third Si site, Si(3) is bonded to two equivalent Gd(1), two equivalent Gd(5), and two equivalent Gd(6) atoms to form edge-sharing SiGd6 octahedra. There are seven inequivalent Br sites. In the first Br site, Br(1) is bonded in a rectangular see-saw-like geometry to one Gd(1), one Gd(3), one Gd(4), and one Gd(5) atom. In the second Br site, Br(2) is bonded in a rectangular see-saw-like geometry to one Gd(2), one Gd(4), one Gd(5), and one Gd(6) atom. In the third Br site, Br(3) is bonded in a rectangular see-saw-like geometry to one Gd(1), one Gd(3), one Gd(5), and one Gd(7) atom. In the fourth Br site, Br(4) is bonded in a rectangular see-saw-like geometry to one Gd(1), one Gd(2), one Gd(3), and one Gd(6) atom. In the fifth Br site, Br(5) is bonded in a rectangular see-saw-like geometry to two equivalent Gd(3) and two equivalent Gd(6) atoms. In the sixth Br site, Br(6) is bonded in a rectangular see-saw-like geometry to one Gd(2), one Gd(5), one Gd(6), and one Gd(7) atom. In the seventh Br site, Br(7) is bonded in a rectangular see-saw-like geometry to two equivalent Gd(1) and two equivalent Gd(2) atoms.
Gd3SiBr3 crystallizes in the monoclinic C2 space group. There are seven inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one Si(1), one Si(3), one Br(1), one Br(3), one Br(4), and one Br(7) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. The Gd(1)-Si(1) bond length is 2.79 Å. The Gd(1)-Si(3) bond length is 2.79 Å. The Gd(1)-Br(1) bond length is 3.00 Å. The Gd(1)-Br(3) bond length is 3.07 Å. The Gd(1)-Br(4) bond length is 3.00 Å. The Gd(1)-Br(7) bond length is 3.07 Å. In the second Gd site, Gd(2) is bonded to one Si(1), one Si(2), one Br(2), one Br(4), one Br(6), and one Br(7) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. The Gd(2)-Si(1) bond length is 2.79 Å. The Gd(2)-Si(2) bond length is 2.80 Å. The Gd(2)-Br(2) bond length is 3.05 Å. The Gd(2)-Br(4) bond length is 3.07 Å. The Gd(2)-Br(6) bond length is 3.00 Å. The Gd(2)-Br(7) bond length is 3.00 Å. In the third Gd site, Gd(3) is bonded to one Si(1), one Si(2), one Br(1), one Br(3), one Br(4), and one Br(5) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. The Gd(3)-Si(1) bond length is 2.79 Å. The Gd(3)-Si(2) bond length is 2.79 Å. The Gd(3)-Br(1) bond length is 3.06 Å. The Gd(3)-Br(3) bond length is 3.00 Å. The Gd(3)-Br(4) bond length is 3.00 Å. The Gd(3)-Br(5) bond length is 3.07 Å. In the fourth Gd site, Gd(4) is bonded to two equivalent Si(1), two equivalent Br(1), and two equivalent Br(2) atoms to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. Both Gd(4)-Si(1) bond lengths are 2.79 Å. Both Gd(4)-Br(1) bond lengths are 3.07 Å. Both Gd(4)-Br(2) bond lengths are 3.00 Å. In the fifth Gd site, Gd(5) is bonded to one Si(2), one Si(3), one Br(1), one Br(2), one Br(3), and one Br(6) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. The Gd(5)-Si(2) bond length is 2.80 Å. The Gd(5)-Si(3) bond length is 2.79 Å. The Gd(5)-Br(1) bond length is 3.00 Å. The Gd(5)-Br(2) bond length is 3.07 Å. The Gd(5)-Br(3) bond length is 3.00 Å. The Gd(5)-Br(6) bond length is 3.07 Å. In the sixth Gd site, Gd(6) is bonded to one Si(1), one Si(3), one Br(2), one Br(4), one Br(5), and one Br(6) atom to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 3-7°. The Gd(6)-Si(1) bond length is 2.79 Å. The Gd(6)-Si(3) bond length is 2.79 Å. The Gd(6)-Br(2) bond length is 3.00 Å. The Gd(6)-Br(4) bond length is 3.07 Å. The Gd(6)-Br(5) bond length is 3.00 Å. The Gd(6)-Br(6) bond length is 3.07 Å. In the seventh Gd site, Gd(7) is bonded to two equivalent Si(1), two equivalent Br(3), and two equivalent Br(6) atoms to form a mixture of corner and edge-sharing GdSi2Br4 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. Both Gd(7)-Si(1) bond lengths are 2.79 Å. Both Gd(7)-Br(3) bond lengths are 3.07 Å. Both Gd(7)-Br(6) bond lengths are 3.00 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one Gd(1), one Gd(2), one Gd(3), one Gd(4), one Gd(6), and one Gd(7) atom to form edge-sharing SiGd6 octahedra. In the second Si site, Si(2) is bonded to two equivalent Gd(2), two equivalent Gd(3), and two equivalent Gd(5) atoms to form edge-sharing SiGd6 octahedra. In the third Si site, Si(3) is bonded to two equivalent Gd(1), two equivalent Gd(5), and two equivalent Gd(6) atoms to form edge-sharing SiGd6 octahedra. There are seven inequivalent Br sites. In the first Br site, Br(1) is bonded in a rectangular see-saw-like geometry to one Gd(1), one Gd(3), one Gd(4), and one Gd(5) atom. In the second Br site, Br(2) is bonded in a rectangular see-saw-like geometry to one Gd(2), one Gd(4), one Gd(5), and one Gd(6) atom. In the third Br site, Br(3) is bonded in a rectangular see-saw-like geometry to one Gd(1), one Gd(3), one Gd(5), and one Gd(7) atom. In the fourth Br site, Br(4) is bonded in a rectangular see-saw-like geometry to one Gd(1), one Gd(2), one Gd(3), and one Gd(6) atom. In the fifth Br site, Br(5) is bonded in a rectangular see-saw-like geometry to two equivalent Gd(3) and two equivalent Gd(6) atoms. In the sixth Br site, Br(6) is bonded in a rectangular see-saw-like geometry to one Gd(2), one Gd(5), one Gd(6), and one Gd(7) atom. In the seventh Br site, Br(7) is bonded in a rectangular see-saw-like geometry to two equivalent Gd(1) and two equivalent Gd(2) atoms.