KCaMg14 crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Ca(1), two equivalent Mg(7), four equivalent Mg(3), and four equivalent Mg(5) atoms to form KCa2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent K(1)Ca2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent Ca(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, and faces with six equivalent Mg(6)CaMg11 cuboctahedra. Ca(1) is bonded to two equivalent K(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form CaK2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Ca(1)K2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with four equivalent Mg(6)CaMg11 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent K(1)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent K(1)Ca2Mg10 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(6)CaMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent Ca(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Ca(1)K2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent K(1)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)CaMg11 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent K(1), two equivalent Ca(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form distorted MgK2Ca2Mg8 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)K2Ca2Mg8 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(6)CaMg11 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent K(1)Ca2Mg10 cuboctahedra, faces with two equivalent Ca(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)KCaMg10 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 K(1)Ca2Mg10 cuboctahedra, corners with four equivalent Ca(1)K2Mg10 cuboctahedra, corners with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, corners with six equivalent Mg(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(6)CaMg11 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 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, and faces with eight equivalent Mg(5)KCaMg10 cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one K(1), one Ca(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form distorted MgKCaMg10 cuboctahedra that share corners with four equivalent Mg(6)CaMg11 cuboctahedra, corners with four equivalent Mg(7)KMg11 cuboctahedra, corners with ten equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with two equivalent Mg(6)CaMg11 cuboctahedra, edges with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with two equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent Mg(7)KMg11 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,  a faceface with one K(1)Ca2Mg10 cuboctahedra,  a faceface with one Ca(1)K2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the sixth Mg site, Mg(6) is bonded to one Ca(1), one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), and four equivalent Mg(5) atoms to form distorted MgCaMg11 cuboctahedra that share corners with four equivalent Mg(7)KMg11 cuboctahedra, corners with six equivalent Mg(6)CaMg11 cuboctahedra, corners with eight equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with two equivalent Mg(7)KMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Ca(1)K2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent K(1)Ca2Mg10 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, and faces with four equivalent Mg(5)KCaMg10 cuboctahedra. In the seventh Mg site, Mg(7) is bonded to one K(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), and four equivalent Mg(5) atoms to form distorted MgKMg11 cuboctahedra that share corners with four equivalent Mg(6)CaMg11 cuboctahedra, corners with six equivalent Mg(7)KMg11 cuboctahedra, corners with eight equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with two equivalent Mg(6)CaMg11 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one K(1)Ca2Mg10 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Ca(1)K2Mg10 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, and faces with four equivalent Mg(5)KCaMg10 cuboctahedra.
KCaMg14 crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Ca(1), two equivalent Mg(7), four equivalent Mg(3), and four equivalent Mg(5) atoms to form KCa2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent K(1)Ca2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent Ca(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, and faces with six equivalent Mg(6)CaMg11 cuboctahedra. Both K(1)-Ca(1) bond lengths are 3.24 Å. Both K(1)-Mg(7) bond lengths are 3.39 Å. There are two shorter (3.33 Å) and two longer (3.35 Å) K(1)-Mg(3) bond lengths. All K(1)-Mg(5) bond lengths are 3.46 Å. Ca(1) is bonded to two equivalent K(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form CaK2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Ca(1)K2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with four equivalent Mg(6)CaMg11 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent K(1)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. Both Ca(1)-Mg(6) bond lengths are 3.36 Å. There are two shorter (3.30 Å) and two longer (3.37 Å) Ca(1)-Mg(3) bond lengths. All Ca(1)-Mg(5) bond lengths are 3.43 Å. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent K(1)Ca2Mg10 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(6)CaMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent Ca(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.24 Å. Both Mg(1)-Mg(6) bond lengths are 3.27 Å. There are two shorter (3.28 Å) and two longer (3.39 Å) Mg(1)-Mg(4) bond lengths. All Mg(1)-Mg(5) bond lengths are 3.14 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Ca(1)K2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KCaMg10 cuboctahedra, faces with two equivalent K(1)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)CaMg11 cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.23 Å. There are two shorter (3.30 Å) and two longer (3.37 Å) Mg(2)-Mg(4) bond lengths. All Mg(2)-Mg(5) bond lengths are 3.15 Å. In the third Mg site, Mg(3) is bonded to two equivalent K(1), two equivalent Ca(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form distorted MgK2Ca2Mg8 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)K2Ca2Mg8 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(6)CaMg11 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent K(1)Ca2Mg10 cuboctahedra, faces with two equivalent Ca(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)KCaMg10 cuboctahedra. There is one shorter (3.22 Å) and one longer (3.27 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.41 Å. Both Mg(3)-Mg(6) bond lengths are 3.28 Å. Both Mg(3)-Mg(7) bond lengths are 3.33 Å. 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 K(1)Ca2Mg10 cuboctahedra, corners with four equivalent Ca(1)K2Mg10 cuboctahedra, corners with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, corners with six equivalent Mg(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(6)CaMg11 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 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, and faces with eight equivalent Mg(5)KCaMg10 cuboctahedra. There is one shorter (3.23 Å) and one longer (3.26 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.11 Å. Both Mg(4)-Mg(6) bond lengths are 3.23 Å. Both Mg(4)-Mg(7) bond lengths are 3.19 Å. In the fifth Mg site, Mg(5) is bonded to one K(1), one Ca(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form distorted MgKCaMg10 cuboctahedra that share corners with four equivalent Mg(6)CaMg11 cuboctahedra, corners with four equivalent Mg(7)KMg11 cuboctahedra, corners with ten equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with two equivalent Mg(6)CaMg11 cuboctahedra, edges with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with two equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent Mg(7)KMg11 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,  a faceface with one K(1)Ca2Mg10 cuboctahedra,  a faceface with one Ca(1)K2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with four equivalent Mg(5)KCaMg10 cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. There is one shorter (3.21 Å) and one longer (3.28 Å) Mg(5)-Mg(5) bond length. There is one shorter (3.26 Å) and one longer (3.42 Å) Mg(5)-Mg(6) bond length. There is one shorter (3.23 Å) and one longer (3.44 Å) Mg(5)-Mg(7) bond length. In the sixth Mg site, Mg(6) is bonded to one Ca(1), one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), and four equivalent Mg(5) atoms to form distorted MgCaMg11 cuboctahedra that share corners with four equivalent Mg(7)KMg11 cuboctahedra, corners with six equivalent Mg(6)CaMg11 cuboctahedra, corners with eight equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent Ca(1)K2Mg10 cuboctahedra, edges with two equivalent Mg(7)KMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Ca(1)K2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent K(1)Ca2Mg10 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, and faces with four equivalent Mg(5)KCaMg10 cuboctahedra. Both Mg(6)-Mg(7) bond lengths are 3.24 Å. In the seventh Mg site, Mg(7) is bonded to one K(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), and four equivalent Mg(5) atoms to form distorted MgKMg11 cuboctahedra that share corners with four equivalent Mg(6)CaMg11 cuboctahedra, corners with six equivalent Mg(7)KMg11 cuboctahedra, corners with eight equivalent Mg(5)KCaMg10 cuboctahedra, edges with two equivalent K(1)Ca2Mg10 cuboctahedra, edges with two equivalent Mg(6)CaMg11 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(3)K2Ca2Mg8 cuboctahedra, edges with four equivalent Mg(5)KCaMg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one K(1)Ca2Mg10 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(6)CaMg11 cuboctahedra, faces with two equivalent Mg(3)K2Ca2Mg8 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Ca(1)K2Mg10 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, and faces with four equivalent Mg(5)KCaMg10 cuboctahedra.