HfTaSi crystallizes in the orthorhombic Amm2 space group. There are eight inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. In the second Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. In the third Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. In the fourth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. In the fifth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. In the sixth Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. In the seventh Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. In the eighth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two Hf(2,2); four Hf(1,1); two equivalent Si(1); and four equivalent Si(2) atoms to form distorted TaHf6Si6 cuboctahedra that share corners with two equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Ta(1)Hf6Si6 cuboctahedra, corners with four equivalent Si(1)Hf6Ta4Si2 cuboctahedra, corners with eight equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, edges with two equivalent Ta(1)Hf6Si6 cuboctahedra, edges with four equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, faces with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, and faces with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra. In the second Ta site, Ta(2) is bonded to two Hf(1,1); four Hf(2,2,2,2); two equivalent Ta(2); two equivalent Ta(3); and two equivalent Si(1) atoms to form distorted TaHf6Ta4Si2 cuboctahedra that share corners with four equivalent Ta(1)Hf6Si6 cuboctahedra, corners with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Si(1)Hf6Ta4Si2 cuboctahedra, edges with two equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, faces with two equivalent Ta(1)Hf6Si6 cuboctahedra, faces with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, faces with four equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, and faces with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra. In the third Ta site, Ta(3) is bonded to two Hf(1,1); four Hf(2,2); four equivalent Ta(2); and two equivalent Si(1) atoms to form distorted TaHf6Ta4Si2 cuboctahedra that share corners with two equivalent Ta(1)Hf6Si6 cuboctahedra, corners with four equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Si(1)Hf6Ta4Si2 cuboctahedra, edges with two equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, edges with four equivalent Ta(1)Hf6Si6 cuboctahedra, faces with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra, and faces with eight equivalent Ta(2)Hf6Ta4Si2 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three Hf(1,1); three Hf(2,2); one Ta(1); one Ta(3); two equivalent Ta(2); and two equivalent Si(2) atoms to form distorted SiHf6Ta4Si2 cuboctahedra that share corners with two equivalent Ta(1)Hf6Si6 cuboctahedra, corners with two equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, edges with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra, faces with two equivalent Si(1)Hf6Ta4Si2 cuboctahedra, faces with three equivalent Ta(1)Hf6Si6 cuboctahedra, faces with three equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, and faces with six equivalent Ta(2)Hf6Ta4Si2 cuboctahedra. In the second Si site, Si(2) is bonded in a 12-coordinate geometry to two Hf(2,2); four Hf(1,1,1,1); two equivalent Ta(1); two equivalent Si(1); and two equivalent Si(2) atoms.
HfTaSi crystallizes in the orthorhombic Amm2 space group. There are eight inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. The Hf(1)-Hf(1) bond length is 3.17 Å. There is one shorter (3.23 Å) and two longer (3.28 Å) Hf(1)-Hf(2,2) bond lengths. The Hf(1)-Ta(3) bond length is 3.14 Å. Both Hf(1)-Ta(1) bond lengths are 3.15 Å. Both Hf(1)-Ta(2) bond lengths are 3.15 Å. There is one shorter (3.10 Å) and two longer (3.16 Å) Hf(1)-Si(1) bond lengths. All Hf(1)-Si(2) bond lengths are 3.09 Å. In the second Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. The Hf(2)-Hf(2) bond length is 3.42 Å. Both Hf(2)-Hf(1) bond lengths are 3.28 Å. The Hf(2)-Ta(1) bond length is 3.05 Å. Both Hf(2)-Ta(3) bond lengths are 3.21 Å. There are two shorter (3.15 Å) and two longer (3.16 Å) Hf(2)-Ta(2) bond lengths. Both Hf(2)-Si(2) bond lengths are 3.02 Å. There is one shorter (3.03 Å) and two longer (3.17 Å) Hf(2)-Si(1) bond lengths. In the third Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. There is one shorter (3.23 Å) and two longer (3.28 Å) Hf(2)-Hf(1,1) bond lengths. The Hf(2)-Ta(1) bond length is 3.05 Å. Both Hf(2)-Ta(3) bond lengths are 3.21 Å. There are two shorter (3.15 Å) and two longer (3.16 Å) Hf(2)-Ta(2) bond lengths. Both Hf(2)-Si(2) bond lengths are 3.02 Å. There is one shorter (3.03 Å) and two longer (3.17 Å) Hf(2)-Si(1) bond lengths. In the fourth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. Both Hf(1)-Hf(2) bond lengths are 3.28 Å. The Hf(1)-Ta(3) bond length is 3.14 Å. Both Hf(1)-Ta(1) bond lengths are 3.15 Å. Both Hf(1)-Ta(2) bond lengths are 3.15 Å. There is one shorter (3.10 Å) and two longer (3.16 Å) Hf(1)-Si(1) bond lengths. All Hf(1)-Si(2) bond lengths are 3.09 Å. In the fifth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. The Hf(1)-Hf(1) bond length is 3.17 Å. The Hf(1)-Hf(2) bond length is 3.23 Å. The Hf(1)-Ta(3) bond length is 3.14 Å. Both Hf(1)-Ta(1) bond lengths are 3.15 Å. Both Hf(1)-Ta(2) bond lengths are 3.15 Å. There is one shorter (3.10 Å) and two longer (3.16 Å) Hf(1)-Si(1) bond lengths. All Hf(1)-Si(2) bond lengths are 3.09 Å. In the sixth Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. The Hf(2)-Hf(2) bond length is 3.42 Å. The Hf(2)-Ta(1) bond length is 3.05 Å. Both Hf(2)-Ta(3) bond lengths are 3.21 Å. There are two shorter (3.15 Å) and two longer (3.16 Å) Hf(2)-Ta(2) bond lengths. Both Hf(2)-Si(2) bond lengths are 3.02 Å. There is one shorter (3.03 Å) and two longer (3.17 Å) Hf(2)-Si(1) bond lengths. In the seventh Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); one Ta(1); two equivalent Ta(3); four equivalent Ta(2); two equivalent Si(2); and three equivalent Si(1) atoms. The Hf(2)-Hf(1) bond length is 3.23 Å. The Hf(2)-Ta(1) bond length is 3.05 Å. Both Hf(2)-Ta(3) bond lengths are 3.21 Å. There are two shorter (3.15 Å) and two longer (3.16 Å) Hf(2)-Ta(2) bond lengths. Both Hf(2)-Si(2) bond lengths are 3.02 Å. There is one shorter (3.03 Å) and two longer (3.17 Å) Hf(2)-Si(1) bond lengths. In the eighth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); one Ta(3); two equivalent Ta(1); two equivalent Ta(2); three equivalent Si(1); and four equivalent Si(2) atoms. The Hf(1)-Ta(3) bond length is 3.14 Å. Both Hf(1)-Ta(1) bond lengths are 3.15 Å. Both Hf(1)-Ta(2) bond lengths are 3.15 Å. There is one shorter (3.10 Å) and two longer (3.16 Å) Hf(1)-Si(1) bond lengths. All Hf(1)-Si(2) bond lengths are 3.09 Å. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two Hf(2,2); four Hf(1,1); two equivalent Si(1); and four equivalent Si(2) atoms to form distorted TaHf6Si6 cuboctahedra that share corners with two equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Ta(1)Hf6Si6 cuboctahedra, corners with four equivalent Si(1)Hf6Ta4Si2 cuboctahedra, corners with eight equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, edges with two equivalent Ta(1)Hf6Si6 cuboctahedra, edges with four equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, faces with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, and faces with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra. Both Ta(1)-Si(1) bond lengths are 2.62 Å. There are two shorter (2.60 Å) and two longer (2.70 Å) Ta(1)-Si(2) bond lengths. In the second Ta site, Ta(2) is bonded to two Hf(1,1); four Hf(2,2,2,2); two equivalent Ta(2); two equivalent Ta(3); and two equivalent Si(1) atoms to form distorted TaHf6Ta4Si2 cuboctahedra that share corners with four equivalent Ta(1)Hf6Si6 cuboctahedra, corners with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Si(1)Hf6Ta4Si2 cuboctahedra, edges with two equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, faces with two equivalent Ta(1)Hf6Si6 cuboctahedra, faces with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, faces with four equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, and faces with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra. There is one shorter (2.65 Å) and one longer (2.79 Å) Ta(2)-Ta(2) bond length. There is one shorter (2.60 Å) and one longer (2.70 Å) Ta(2)-Ta(3) bond length. Both Ta(2)-Si(1) bond lengths are 2.69 Å. In the third Ta site, Ta(3) is bonded to two Hf(1,1); four Hf(2,2); four equivalent Ta(2); and two equivalent Si(1) atoms to form distorted TaHf6Ta4Si2 cuboctahedra that share corners with two equivalent Ta(1)Hf6Si6 cuboctahedra, corners with four equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Si(1)Hf6Ta4Si2 cuboctahedra, edges with two equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, edges with four equivalent Ta(1)Hf6Si6 cuboctahedra, faces with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra, and faces with eight equivalent Ta(2)Hf6Ta4Si2 cuboctahedra. Both Ta(3)-Si(1) bond lengths are 2.68 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three Hf(1,1); three Hf(2,2); one Ta(1); one Ta(3); two equivalent Ta(2); and two equivalent Si(2) atoms to form distorted SiHf6Ta4Si2 cuboctahedra that share corners with two equivalent Ta(1)Hf6Si6 cuboctahedra, corners with two equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, corners with four equivalent Ta(2)Hf6Ta4Si2 cuboctahedra, edges with six equivalent Si(1)Hf6Ta4Si2 cuboctahedra, faces with two equivalent Si(1)Hf6Ta4Si2 cuboctahedra, faces with three equivalent Ta(1)Hf6Si6 cuboctahedra, faces with three equivalent Ta(3)Hf6Ta4Si2 cuboctahedra, and faces with six equivalent Ta(2)Hf6Ta4Si2 cuboctahedra. Both Si(1)-Si(2) bond lengths are 2.73 Å. In the second Si site, Si(2) is bonded in a 12-coordinate geometry to two Hf(2,2); four Hf(1,1,1,1); two equivalent Ta(1); two equivalent Si(1); and two equivalent Si(2) atoms. There is one shorter (2.57 Å) and one longer (2.87 Å) Si(2)-Si(2) bond length.