Mg4Si3 is Magnesium tetraboride-like structured and crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(2) and two equivalent Si(3) atoms. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), one Si(1), one Si(2), and one Si(3) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(2), two equivalent Mg(4), one Si(1), and one Si(2) atom. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Si(1) atom.
Mg4Si3 is Magnesium tetraboride-like structured and crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(3) atoms. The Mg(1)-Si(2) bond length is 2.67 Å. There is one shorter (2.66 Å) and one longer (2.84 Å) Mg(1)-Si(3) bond length. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(2) and two equivalent Si(3) atoms. There is one shorter (2.70 Å) and one longer (2.93 Å) Mg(2)-Si(2) bond length. There is one shorter (2.71 Å) and one longer (2.75 Å) Mg(2)-Si(3) bond length. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(1) atoms. The Mg(3)-Si(2) bond length is 2.91 Å. The Mg(3)-Si(3) bond length is 2.84 Å. There is one shorter (2.88 Å) and one longer (3.17 Å) Mg(3)-Si(1) bond length. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There is one shorter (2.77 Å) and one longer (2.85 Å) Mg(4)-Si(1) bond length. There is one shorter (2.87 Å) and one longer (2.90 Å) Mg(4)-Si(2) bond length. There is one shorter (2.78 Å) and one longer (2.83 Å) Mg(4)-Si(3) bond length. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), one Si(1), one Si(2), and one Si(3) atom. The Si(1)-Si(1) bond length is 2.59 Å. The Si(1)-Si(2) bond length is 2.44 Å. The Si(1)-Si(3) bond length is 2.42 Å. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(2), two equivalent Mg(4), one Si(1), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.49 Å. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Si(1) atom.