Sc5Hf5Si6 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. In the second Sc site, Sc(2) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(1), and two equivalent Si(4) atoms. In the third Sc site, Sc(3) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 6-coordinate geometry to one Si(1), one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. In the second Hf site, Hf(2) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sc(1), two equivalent Sc(2), one Hf(2), and four equivalent Hf(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Sc(1), two equivalent Sc(3), one Hf(2), and four equivalent Hf(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Sc(2), two equivalent Sc(3), two equivalent Hf(2), and four equivalent Hf(1) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Sc(2), two equivalent Sc(1), two equivalent Sc(3), and four equivalent Hf(1) atoms.
Sc5Hf5Si6 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. The Sc(1)-Si(1) bond length is 2.74 Å. There is one shorter (2.72 Å) and one longer (2.86 Å) Sc(1)-Si(2) bond length. Both Sc(1)-Si(4) bond lengths are 3.09 Å. In the second Sc site, Sc(2) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(1), and two equivalent Si(4) atoms. The Sc(2)-Si(3) bond length is 2.84 Å. Both Sc(2)-Si(1) bond lengths are 3.09 Å. Both Sc(2)-Si(4) bond lengths are 2.74 Å. In the third Sc site, Sc(3) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. The Sc(3)-Si(3) bond length is 2.72 Å. Both Sc(3)-Si(2) bond lengths are 3.08 Å. There is one shorter (2.73 Å) and one longer (2.84 Å) Sc(3)-Si(4) bond length. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 6-coordinate geometry to one Si(1), one Si(3), two equivalent Si(2), and two equivalent Si(4) atoms. The Hf(1)-Si(1) bond length is 2.81 Å. The Hf(1)-Si(3) bond length is 2.81 Å. There is one shorter (2.80 Å) and one longer (2.82 Å) Hf(1)-Si(2) bond length. Both Hf(1)-Si(4) bond lengths are 2.81 Å. In the second Hf site, Hf(2) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. The Hf(2)-Si(1) bond length is 2.81 Å. Both Hf(2)-Si(2) bond lengths are 2.73 Å. Both Hf(2)-Si(3) bond lengths are 3.07 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sc(1), two equivalent Sc(2), one Hf(2), and four equivalent Hf(1) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Sc(1), two equivalent Sc(3), one Hf(2), and four equivalent Hf(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Sc(2), two equivalent Sc(3), two equivalent Hf(2), and four equivalent Hf(1) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Sc(2), two equivalent Sc(1), two equivalent Sc(3), and four equivalent Hf(1) atoms.