Hf4CuSi3 crystallizes in the orthorhombic Pmm2 space group. There are four inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 7-coordinate geometry to one Cu(1), two equivalent Si(1), and four equivalent Si(2) atoms. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to two equivalent Cu(1), one Si(1), and four equivalent Si(3) atoms. In the third Hf site, Hf(3) is bonded in a 7-coordinate geometry to four equivalent Cu(1), one Si(2), and two equivalent Si(3) atoms. In the fourth Hf site, Hf(4) is bonded in a 7-coordinate geometry to one Si(3), two equivalent Si(2), and four equivalent Si(1) atoms. Cu(1) is bonded in a 9-coordinate geometry to one Hf(1), two equivalent Hf(2), four equivalent Hf(3), and two equivalent Si(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Hf(2), two equivalent Hf(1), four equivalent Hf(4), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Hf(3), two equivalent Hf(4), four equivalent Hf(1), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Hf(4), two equivalent Hf(3), four equivalent Hf(2), and two equivalent Cu(1) atoms.
Hf4CuSi3 crystallizes in the orthorhombic Pmm2 space group. There are four inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 7-coordinate geometry to one Cu(1), two equivalent Si(1), and four equivalent Si(2) atoms. The Hf(1)-Cu(1) bond length is 2.79 Å. Both Hf(1)-Si(1) bond lengths are 2.92 Å. All Hf(1)-Si(2) bond lengths are 2.71 Å. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to two equivalent Cu(1), one Si(1), and four equivalent Si(3) atoms. Both Hf(2)-Cu(1) bond lengths are 2.89 Å. The Hf(2)-Si(1) bond length is 2.70 Å. All Hf(2)-Si(3) bond lengths are 2.74 Å. In the third Hf site, Hf(3) is bonded in a 7-coordinate geometry to four equivalent Cu(1), one Si(2), and two equivalent Si(3) atoms. All Hf(3)-Cu(1) bond lengths are 2.74 Å. The Hf(3)-Si(2) bond length is 2.71 Å. Both Hf(3)-Si(3) bond lengths are 2.89 Å. In the fourth Hf site, Hf(4) is bonded in a 7-coordinate geometry to one Si(3), two equivalent Si(2), and four equivalent Si(1) atoms. The Hf(4)-Si(3) bond length is 2.77 Å. Both Hf(4)-Si(2) bond lengths are 2.93 Å. All Hf(4)-Si(1) bond lengths are 2.72 Å. Cu(1) is bonded in a 9-coordinate geometry to one Hf(1), two equivalent Hf(2), four equivalent Hf(3), and two equivalent Si(3) atoms. Both Cu(1)-Si(3) bond lengths are 2.38 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Hf(2), two equivalent Hf(1), four equivalent Hf(4), and two equivalent Si(2) atoms. Both Si(1)-Si(2) bond lengths are 2.46 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Hf(3), two equivalent Hf(4), four equivalent Hf(1), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Hf(4), two equivalent Hf(3), four equivalent Hf(2), and two equivalent Cu(1) atoms.