Mg14MnSi crystallizes in the orthorhombic Amm2 space group. There are ten inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2); two equivalent Mg(6); four Mg(4,4,4); and four Mg(5,5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six equivalent Mg(1)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mn(1)Mg10Si2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with six equivalent Mg(7)Mg11Si cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1); two equivalent Mg(7); four Mg(4,4,4); and four Mg(5,5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with six equivalent Mg(2)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Si(1)Mg10Mn2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with six equivalent Mg(6)Mg11Mn cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Mn(1), and two equivalent Si(1) atoms to form distorted MgMg8Mn2Si2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra; corners with four equivalent Mg(2)Mg12 cuboctahedra; corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with six equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra; edges with four equivalent Mg(5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; faces with two equivalent Mn(1)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10Mn2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six Mg(4,4)Mg12 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. In the fifth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six Mg(4,4)Mg12 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with four Mg(5,5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. In the sixth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Mn(1), and one Si(1) atom to form distorted MgMg10MnSi cuboctahedra that share corners with four equivalent Mg(6)Mg11Mn cuboctahedra; corners with four equivalent Mg(7)Mg11Si cuboctahedra; corners with ten Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(6)Mg11Mn cuboctahedra; edges with two equivalent Mg(7)Mg11Si cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one Mn(1)Mg10Si2 cuboctahedra;  a faceface with one Si(1)Mg10Mn2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra. In the seventh Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Mn(1), and one Si(1) atom to form distorted MgMg10MnSi cuboctahedra that share corners with four equivalent Mg(6)Mg11Mn cuboctahedra; corners with four equivalent Mg(7)Mg11Si cuboctahedra; corners with ten Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(6)Mg11Mn cuboctahedra; edges with two equivalent Mg(7)Mg11Si cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one Mn(1)Mg10Si2 cuboctahedra;  a faceface with one Si(1)Mg10Mn2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra. In the eighth Mg site, Mg(6) is bonded to one Mg(1); two equivalent Mg(3); two Mg(4,4); two equivalent Mg(7); four Mg(5,5); and one Mn(1) atom to form MgMg11Mn cuboctahedra that share corners with four equivalent Mg(7)Mg11Si cuboctahedra; corners with six equivalent Mg(6)Mg11Mn cuboctahedra; corners with eight Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(7)Mg11Si cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with four Mg(5,5)Mg10MnSi cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mn(1)Mg10Si2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two Mg(4,4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; faces with three equivalent Mg(2)Mg12 cuboctahedra; faces with three equivalent Si(1)Mg10Mn2 cuboctahedra; and faces with four Mg(5,5)Mg10MnSi cuboctahedra. In the ninth Mg site, Mg(7) is bonded to one Mg(2); two equivalent Mg(3); two Mg(4,4); two equivalent Mg(6); four Mg(5,5); and one Si(1) atom to form distorted MgMg11Si cuboctahedra that share corners with four equivalent Mg(6)Mg11Mn cuboctahedra; corners with six equivalent Mg(7)Mg11Si cuboctahedra; corners with eight Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(6)Mg11Mn cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra; edges with four Mg(5,5)Mg10MnSi cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one Si(1)Mg10Mn2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two Mg(4,4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; faces with three equivalent Mg(1)Mg12 cuboctahedra; faces with three equivalent Mn(1)Mg10Si2 cuboctahedra; and faces with four Mg(5,5)Mg10MnSi cuboctahedra. In the tenth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six Mg(4,4)Mg12 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. Mn(1) is bonded to two equivalent Mg(6); four equivalent Mg(3); four Mg(5,5); and two equivalent Si(1) atoms to form MnMg10Si2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra; corners with six equivalent Mn(1)Mg10Si2 cuboctahedra; corners with eight Mg(4,4,4)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Si(1)Mg10Mn2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with six equivalent Mg(7)Mg11Si cuboctahedra. Si(1) is bonded to two equivalent Mg(7); four equivalent Mg(3); four Mg(5,5); and two equivalent Mn(1) atoms to form SiMg10Mn2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra; corners with six equivalent Si(1)Mg10Mn2 cuboctahedra; corners with eight Mg(4,4,4)Mg12 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mn(1)Mg10Si2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with six equivalent Mg(6)Mg11Mn cuboctahedra.
Mg14MnSi crystallizes in the orthorhombic Amm2 space group. There are ten inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2); two equivalent Mg(6); four Mg(4,4,4); and four Mg(5,5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six equivalent Mg(1)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mn(1)Mg10Si2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with six equivalent Mg(7)Mg11Si cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.11 Å. Both Mg(1)-Mg(6) bond lengths are 3.14 Å. There are two shorter (3.09 Å) and two longer (3.14 Å) Mg(1)-Mg(4,4,4) bond lengths. All Mg(1)-Mg(5,5) bond lengths are 3.22 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1); two equivalent Mg(7); four Mg(4,4,4); and four Mg(5,5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with six equivalent Mg(2)Mg12 cuboctahedra; corners with eight equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Si(1)Mg10Mn2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with six equivalent Mg(6)Mg11Mn cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.14 Å. There are two shorter (3.10 Å) and two longer (3.12 Å) Mg(2)-Mg(4,4,4) bond lengths. All Mg(2)-Mg(5,5) bond lengths are 3.22 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Mn(1), and two equivalent Si(1) atoms to form distorted MgMg8Mn2Si2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra; corners with four equivalent Mg(2)Mg12 cuboctahedra; corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with six equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra; edges with four equivalent Mg(5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; faces with two equivalent Mn(1)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10Mn2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. There is one shorter (3.09 Å) and one longer (3.13 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.03 Å. Both Mg(3)-Mg(6) bond lengths are 3.07 Å. Both Mg(3)-Mg(7) bond lengths are 3.07 Å. There is one shorter (3.05 Å) and one longer (3.17 Å) Mg(3)-Mn(1) bond length. There is one shorter (3.06 Å) and one longer (3.16 Å) Mg(3)-Si(1) bond length. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six Mg(4,4)Mg12 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. There is one shorter (3.10 Å) and one longer (3.12 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.24 Å. Both Mg(4)-Mg(6) bond lengths are 3.16 Å. Both Mg(4)-Mg(7) bond lengths are 3.16 Å. In the fifth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six Mg(4,4)Mg12 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with four Mg(5,5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. Both Mg(4)-Mg(5) bond lengths are 3.24 Å. Both Mg(4)-Mg(6) bond lengths are 3.16 Å. Both Mg(4)-Mg(7) bond lengths are 3.16 Å. In the sixth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Mn(1), and one Si(1) atom to form distorted MgMg10MnSi cuboctahedra that share corners with four equivalent Mg(6)Mg11Mn cuboctahedra; corners with four equivalent Mg(7)Mg11Si cuboctahedra; corners with ten Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(6)Mg11Mn cuboctahedra; edges with two equivalent Mg(7)Mg11Si cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one Mn(1)Mg10Si2 cuboctahedra;  a faceface with one Si(1)Mg10Mn2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra. There is one shorter (3.10 Å) and one longer (3.11 Å) Mg(5)-Mg(5) bond length. There is one shorter (3.06 Å) and one longer (3.16 Å) Mg(5)-Mg(6) bond length. There is one shorter (3.07 Å) and one longer (3.16 Å) Mg(5)-Mg(7) bond length. The Mg(5)-Mn(1) bond length is 2.99 Å. The Mg(5)-Si(1) bond length is 2.99 Å. In the seventh Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Mn(1), and one Si(1) atom to form distorted MgMg10MnSi cuboctahedra that share corners with four equivalent Mg(6)Mg11Mn cuboctahedra; corners with four equivalent Mg(7)Mg11Si cuboctahedra; corners with ten Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(6)Mg11Mn cuboctahedra; edges with two equivalent Mg(7)Mg11Si cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one Mn(1)Mg10Si2 cuboctahedra;  a faceface with one Si(1)Mg10Mn2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four Mg(4,4,4)Mg12 cuboctahedra; and faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra. The Mg(5)-Mg(3) bond length is 3.03 Å. There is one shorter (3.06 Å) and one longer (3.16 Å) Mg(5)-Mg(6) bond length. There is one shorter (3.07 Å) and one longer (3.16 Å) Mg(5)-Mg(7) bond length. The Mg(5)-Mn(1) bond length is 2.99 Å. The Mg(5)-Si(1) bond length is 2.99 Å. In the eighth Mg site, Mg(6) is bonded to one Mg(1); two equivalent Mg(3); two Mg(4,4); two equivalent Mg(7); four Mg(5,5); and one Mn(1) atom to form MgMg11Mn cuboctahedra that share corners with four equivalent Mg(7)Mg11Si cuboctahedra; corners with six equivalent Mg(6)Mg11Mn cuboctahedra; corners with eight Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(7)Mg11Si cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with four Mg(5,5)Mg10MnSi cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra;  a faceface with one Mg(1)Mg12 cuboctahedra;  a faceface with one Mn(1)Mg10Si2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two Mg(4,4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; faces with three equivalent Mg(2)Mg12 cuboctahedra; faces with three equivalent Si(1)Mg10Mn2 cuboctahedra; and faces with four Mg(5,5)Mg10MnSi cuboctahedra. Both Mg(6)-Mg(7) bond lengths are 3.11 Å. The Mg(6)-Mn(1) bond length is 3.04 Å. In the ninth Mg site, Mg(7) is bonded to one Mg(2); two equivalent Mg(3); two Mg(4,4); two equivalent Mg(6); four Mg(5,5); and one Si(1) atom to form distorted MgMg11Si cuboctahedra that share corners with four equivalent Mg(6)Mg11Mn cuboctahedra; corners with six equivalent Mg(7)Mg11Si cuboctahedra; corners with eight Mg(5,5)Mg10MnSi cuboctahedra; edges with two equivalent Mg(6)Mg11Mn cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra; edges with four Mg(5,5)Mg10MnSi cuboctahedra; edges with four Mg(4,4,4)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra;  a faceface with one Mg(2)Mg12 cuboctahedra;  a faceface with one Si(1)Mg10Mn2 cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two Mg(4,4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; faces with three equivalent Mg(1)Mg12 cuboctahedra; faces with three equivalent Mn(1)Mg10Si2 cuboctahedra; and faces with four Mg(5,5)Mg10MnSi cuboctahedra. The Mg(7)-Si(1) bond length is 3.04 Å. In the tenth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; corners with four equivalent Mn(1)Mg10Si2 cuboctahedra; corners with four equivalent Si(1)Mg10Mn2 cuboctahedra; corners with six Mg(4,4)Mg12 cuboctahedra; edges with two equivalent Mg(1)Mg12 cuboctahedra; edges with two equivalent Mg(2)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with four equivalent Mg(5)Mg10MnSi cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with eight Mg(5,5)Mg10MnSi cuboctahedra. There is one shorter (3.10 Å) and one longer (3.12 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.24 Å. Both Mg(4)-Mg(6) bond lengths are 3.16 Å. Both Mg(4)-Mg(7) bond lengths are 3.16 Å. Mn(1) is bonded to two equivalent Mg(6); four equivalent Mg(3); four Mg(5,5); and two equivalent Si(1) atoms to form MnMg10Si2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra; corners with six equivalent Mn(1)Mg10Si2 cuboctahedra; corners with eight Mg(4,4,4)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg10Mn2 cuboctahedra; edges with four equivalent Mg(6)Mg11Mn cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(6)Mg11Mn cuboctahedra; faces with two equivalent Mg(1)Mg12 cuboctahedra; faces with two equivalent Si(1)Mg10Mn2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with six equivalent Mg(7)Mg11Si cuboctahedra. Both Mn(1)-Si(1) bond lengths are 3.11 Å. Si(1) is bonded to two equivalent Mg(7); four equivalent Mg(3); four Mg(5,5); and two equivalent Mn(1) atoms to form SiMg10Mn2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra; corners with six equivalent Si(1)Mg10Mn2 cuboctahedra; corners with eight Mg(4,4,4)Mg12 cuboctahedra; edges with two equivalent Mn(1)Mg10Si2 cuboctahedra; edges with four equivalent Mg(7)Mg11Si cuboctahedra; edges with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; edges with eight Mg(5,5)Mg10MnSi cuboctahedra; faces with two equivalent Mg(7)Mg11Si cuboctahedra; faces with two equivalent Mg(2)Mg12 cuboctahedra; faces with two equivalent Mn(1)Mg10Si2 cuboctahedra; faces with four Mg(5,5)Mg10MnSi cuboctahedra; faces with four equivalent Mg(3)Mg8Mn2Si2 cuboctahedra; and faces with six equivalent Mg(6)Mg11Mn cuboctahedra.