LiMg14Si crystallizes in the hexagonal P-6m2 space group. Li(1) is bonded to six equivalent Mg(1) and six Mg(3,3) atoms to form LiMg12 cuboctahedra that share corners with six equivalent Li(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Mg10Si2 cuboctahedra; edges with six equivalent Mg(1)Li2Mg10 cuboctahedra; edges with twelve Mg(3,3)LiMg10Si cuboctahedra; faces with two equivalent Si(1)Mg12 cuboctahedra; faces with six equivalent Mg(1)Li2Mg10 cuboctahedra; faces with six Mg(3,3)LiMg10Si cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Li(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgLi2Mg10 cuboctahedra that share corners with four equivalent Si(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Li2Mg10 cuboctahedra; corners with eight equivalent Mg(2)Mg10Si2 cuboctahedra; edges with two equivalent Li(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Li2Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)LiMg10Si cuboctahedra; faces with two equivalent Li(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Si2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(1)Li2Mg10 cuboctahedra; and faces with ten Mg(3,3)LiMg10Si cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with four equivalent Li(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Si2 cuboctahedra; corners with eight equivalent Mg(1)Li2Mg10 cuboctahedra; edges with two equivalent Si(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Mg10Si2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)LiMg10Si cuboctahedra; faces with two equivalent Mg(1)Li2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Si(1)Mg12 cuboctahedra; faces with four equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with ten Mg(3,3)LiMg10Si cuboctahedra. In the third Mg site, Mg(3) is bonded to one Li(1); two equivalent Mg(1); two equivalent Mg(2); two equivalent Mg(4); four Mg(3,3); and one Si(1) atom to form distorted MgLiMg10Si cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)LiMg10Si cuboctahedra; edges with two equivalent Li(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Li2Mg10 cuboctahedra; edges with four Mg(3,3)LiMg10Si cuboctahedra; edges with four equivalent Mg(2)Mg10Si2 cuboctahedra;  a faceface with one Li(1)Mg12 cuboctahedra;  a faceface with one Si(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Li2Mg10 cuboctahedra; faces with five equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with six Mg(3,3)LiMg10Si cuboctahedra. In the fourth Mg site, Mg(3) is bonded to one Li(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(3), and one Si(1) atom to form distorted MgLiMg10Si cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)LiMg10Si cuboctahedra; edges with two equivalent Li(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Li2Mg10 cuboctahedra; edges with four equivalent Mg(3)LiMg10Si cuboctahedra; edges with four equivalent Mg(2)Mg10Si2 cuboctahedra;  a faceface with one Li(1)Mg12 cuboctahedra;  a faceface with one Si(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Li2Mg10 cuboctahedra; faces with five equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with six Mg(3,3)LiMg10Si cuboctahedra. In the fifth Mg site, Mg(4) is bonded to three equivalent Mg(1); three equivalent Mg(2); and six Mg(3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve Mg(3,3)LiMg10Si cuboctahedra; edges with six equivalent Mg(1)Li2Mg10 cuboctahedra; edges with six Mg(3,3)LiMg10Si cuboctahedra; edges with six equivalent Mg(2)Mg10Si2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three equivalent Li(1)Mg12 cuboctahedra; faces with three equivalent Mg(1)Li2Mg10 cuboctahedra; faces with three equivalent Mg(2)Mg10Si2 cuboctahedra; faces with three equivalent Si(1)Mg12 cuboctahedra; and faces with six Mg(3,3)LiMg10Si cuboctahedra. Si(1) is bonded to six equivalent Mg(2) and six Mg(3,3) atoms to form SiMg12 cuboctahedra that share corners with six equivalent Si(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(1)Li2Mg10 cuboctahedra; edges with six equivalent Mg(2)Mg10Si2 cuboctahedra; edges with twelve Mg(3,3)LiMg10Si cuboctahedra; faces with two equivalent Li(1)Mg12 cuboctahedra; faces with six Mg(3,3)LiMg10Si cuboctahedra; faces with six equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.
LiMg14Si crystallizes in the hexagonal P-6m2 space group. Li(1) is bonded to six equivalent Mg(1) and six Mg(3,3) atoms to form LiMg12 cuboctahedra that share corners with six equivalent Li(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Mg10Si2 cuboctahedra; edges with six equivalent Mg(1)Li2Mg10 cuboctahedra; edges with twelve Mg(3,3)LiMg10Si cuboctahedra; faces with two equivalent Si(1)Mg12 cuboctahedra; faces with six equivalent Mg(1)Li2Mg10 cuboctahedra; faces with six Mg(3,3)LiMg10Si cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. All Li(1)-Mg(1) bond lengths are 3.13 Å. All Li(1)-Mg(3,3) bond lengths are 3.16 Å. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Li(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgLi2Mg10 cuboctahedra that share corners with four equivalent Si(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Li2Mg10 cuboctahedra; corners with eight equivalent Mg(2)Mg10Si2 cuboctahedra; edges with two equivalent Li(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Li2Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)LiMg10Si cuboctahedra; faces with two equivalent Li(1)Mg12 cuboctahedra; faces with two equivalent Mg(2)Mg10Si2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with four equivalent Mg(1)Li2Mg10 cuboctahedra; and faces with ten Mg(3,3)LiMg10Si cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.15 Å. There are two shorter (3.11 Å) and two longer (3.14 Å) Mg(1)-Mg(1) bond lengths. All Mg(1)-Mg(3) bond lengths are 3.18 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with four equivalent Li(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Si2 cuboctahedra; corners with eight equivalent Mg(1)Li2Mg10 cuboctahedra; edges with two equivalent Si(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Mg10Si2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)LiMg10Si cuboctahedra; faces with two equivalent Mg(1)Li2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Si(1)Mg12 cuboctahedra; faces with four equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with ten Mg(3,3)LiMg10Si cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.17 Å. There are two shorter (3.11 Å) and two longer (3.14 Å) Mg(2)-Mg(2) bond lengths. All Mg(2)-Mg(3) bond lengths are 3.16 Å. Both Mg(2)-Si(1) bond lengths are 3.13 Å. In the third Mg site, Mg(3) is bonded to one Li(1); two equivalent Mg(1); two equivalent Mg(2); two equivalent Mg(4); four Mg(3,3); and one Si(1) atom to form distorted MgLiMg10Si cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)LiMg10Si cuboctahedra; edges with two equivalent Li(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Li2Mg10 cuboctahedra; edges with four Mg(3,3)LiMg10Si cuboctahedra; edges with four equivalent Mg(2)Mg10Si2 cuboctahedra;  a faceface with one Li(1)Mg12 cuboctahedra;  a faceface with one Si(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Li2Mg10 cuboctahedra; faces with five equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with six Mg(3,3)LiMg10Si cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.13 Å. There are two shorter (3.09 Å) and two longer (3.16 Å) Mg(3)-Mg(3,3) bond lengths. The Mg(3)-Si(1) bond length is 3.13 Å. In the fourth Mg site, Mg(3) is bonded to one Li(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(3), and one Si(1) atom to form distorted MgLiMg10Si cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen Mg(3,3)LiMg10Si cuboctahedra; edges with two equivalent Li(1)Mg12 cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Si(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Li2Mg10 cuboctahedra; edges with four equivalent Mg(3)LiMg10Si cuboctahedra; edges with four equivalent Mg(2)Mg10Si2 cuboctahedra;  a faceface with one Li(1)Mg12 cuboctahedra;  a faceface with one Si(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five equivalent Mg(1)Li2Mg10 cuboctahedra; faces with five equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with six Mg(3,3)LiMg10Si cuboctahedra. Both Mg(3)-Mg(1) bond lengths are 3.18 Å. Both Mg(3)-Mg(2) bond lengths are 3.16 Å. Both Mg(3)-Mg(4) bond lengths are 3.13 Å. The Mg(3)-Si(1) bond length is 3.13 Å. In the fifth Mg site, Mg(4) is bonded to three equivalent Mg(1); three equivalent Mg(2); and six Mg(3,3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve Mg(3,3)LiMg10Si cuboctahedra; edges with six equivalent Mg(1)Li2Mg10 cuboctahedra; edges with six Mg(3,3)LiMg10Si cuboctahedra; edges with six equivalent Mg(2)Mg10Si2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three equivalent Li(1)Mg12 cuboctahedra; faces with three equivalent Mg(1)Li2Mg10 cuboctahedra; faces with three equivalent Mg(2)Mg10Si2 cuboctahedra; faces with three equivalent Si(1)Mg12 cuboctahedra; and faces with six Mg(3,3)LiMg10Si cuboctahedra. Si(1) is bonded to six equivalent Mg(2) and six Mg(3,3) atoms to form SiMg12 cuboctahedra that share corners with six equivalent Si(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(1)Li2Mg10 cuboctahedra; edges with six equivalent Mg(2)Mg10Si2 cuboctahedra; edges with twelve Mg(3,3)LiMg10Si cuboctahedra; faces with two equivalent Li(1)Mg12 cuboctahedra; faces with six Mg(3,3)LiMg10Si cuboctahedra; faces with six equivalent Mg(2)Mg10Si2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.