Mg16Al12P crystallizes in the trigonal R3m space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted single-bond geometry to three equivalent Mg(2), three equivalent Al(1), three equivalent Al(2), six equivalent Al(3), and one P(1) atom. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(5), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(4), four equivalent Mg(5), one Al(1), two equivalent Al(2), two equivalent Al(3), and one P(1) atom. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to one Mg(2), two equivalent Mg(3), four equivalent Mg(5), one Al(2), and four equivalent Al(3) atoms. In the fifth Mg site, Mg(5) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), one Al(2), two equivalent Al(1), and two equivalent Al(3) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(2), four equivalent Mg(5), one Al(2), and two equivalent Al(3) atoms. In the second Al site, Al(2) is bonded in a distorted q6 geometry to one Mg(1), one Mg(4), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(5), one Al(1), and two equivalent Al(2) atoms. In the third Al site, Al(3) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), two equivalent Mg(4), two equivalent Mg(5), one Al(1), two equivalent Al(3), and one P(1) atom. P(1) is bonded in a 10-coordinate geometry to one Mg(1), three equivalent Mg(3), and six equivalent Al(3) atoms.
Mg16Al12P crystallizes in the trigonal R3m space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted single-bond geometry to three equivalent Mg(2), three equivalent Al(1), three equivalent Al(2), six equivalent Al(3), and one P(1) atom. All Mg(1)-Mg(2) bond lengths are 3.14 Å. All Mg(1)-Al(1) bond lengths are 3.27 Å. All Mg(1)-Al(2) bond lengths are 3.14 Å. All Mg(1)-Al(3) bond lengths are 3.22 Å. The Mg(1)-P(1) bond length is 2.70 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(5), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. The Mg(2)-Mg(4) bond length is 3.01 Å. Both Mg(2)-Mg(5) bond lengths are 3.03 Å. Both Mg(2)-Al(1) bond lengths are 3.14 Å. Both Mg(2)-Al(2) bond lengths are 3.05 Å. Both Mg(2)-Al(3) bond lengths are 3.13 Å. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(4), four equivalent Mg(5), one Al(1), two equivalent Al(2), two equivalent Al(3), and one P(1) atom. Both Mg(3)-Mg(4) bond lengths are 3.08 Å. There are two shorter (3.20 Å) and two longer (3.32 Å) Mg(3)-Mg(5) bond lengths. The Mg(3)-Al(1) bond length is 3.08 Å. Both Mg(3)-Al(2) bond lengths are 2.95 Å. Both Mg(3)-Al(3) bond lengths are 3.12 Å. The Mg(3)-P(1) bond length is 3.01 Å. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to one Mg(2), two equivalent Mg(3), four equivalent Mg(5), one Al(2), and four equivalent Al(3) atoms. There are two shorter (3.09 Å) and two longer (3.14 Å) Mg(4)-Mg(5) bond lengths. The Mg(4)-Al(2) bond length is 2.99 Å. There are two shorter (3.02 Å) and two longer (3.09 Å) Mg(4)-Al(3) bond lengths. In the fifth Mg site, Mg(5) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), one Al(2), two equivalent Al(1), and two equivalent Al(3) atoms. The Mg(5)-Al(2) bond length is 3.07 Å. There is one shorter (2.95 Å) and one longer (3.12 Å) Mg(5)-Al(1) bond length. There is one shorter (2.88 Å) and one longer (2.97 Å) Mg(5)-Al(3) bond length. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(2), four equivalent Mg(5), one Al(2), and two equivalent Al(3) atoms. The Al(1)-Al(2) bond length is 2.70 Å. Both Al(1)-Al(3) bond lengths are 2.75 Å. In the second Al site, Al(2) is bonded in a distorted q6 geometry to one Mg(1), one Mg(4), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(5), one Al(1), and two equivalent Al(2) atoms. Both Al(2)-Al(2) bond lengths are 2.78 Å. In the third Al site, Al(3) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), two equivalent Mg(4), two equivalent Mg(5), one Al(1), two equivalent Al(3), and one P(1) atom. There is one shorter (2.72 Å) and one longer (2.75 Å) Al(3)-Al(3) bond length. The Al(3)-P(1) bond length is 2.91 Å. P(1) is bonded in a 10-coordinate geometry to one Mg(1), three equivalent Mg(3), and six equivalent Al(3) atoms.