SrMg5 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Sr(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(2) atoms to form distorted SrSr2Mg10 cuboctahedra that share corners with six equivalent Sr(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(4)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with eight equivalent Mg(1)Mg10 cuboctahedra, faces with two equivalent Mg(1)Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(5)Sr2Mg10 cuboctahedra, and faces with four equivalent Sr(1)Sr2Mg10 cuboctahedra. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(5) atoms to form distorted MgMg10 cuboctahedra that share corners with four equivalent Mg(1)Mg10 cuboctahedra, corners with four equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with eight equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with four equivalent Mg(1)Mg10 cuboctahedra, faces with four equivalent Mg(5)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Sr2Mg10 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to four equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(5) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(3), and four equivalent Mg(4) atoms. In the fourth Mg site, Mg(4) is bonded to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with six equivalent Sr(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with three equivalent Sr(1)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(5)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(5)Sr2Mg10 cuboctahedra, faces with four equivalent Mg(4)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(1)Mg10 cuboctahedra. In the fifth Mg site, Mg(5) is bonded to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(1) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg10 cuboctahedra, corners with six equivalent Sr(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with three equivalent Sr(1)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with four equivalent Mg(1)Mg10 cuboctahedra, and faces with four equivalent Mg(5)Sr2Mg10 cuboctahedra.
SrMg5 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Sr(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(2) atoms to form distorted SrSr2Mg10 cuboctahedra that share corners with six equivalent Sr(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(4)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with eight equivalent Mg(1)Mg10 cuboctahedra, faces with two equivalent Mg(1)Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(5)Sr2Mg10 cuboctahedra, and faces with four equivalent Sr(1)Sr2Mg10 cuboctahedra. Both Sr(1)-Sr(1) bond lengths are 3.51 Å. Both Sr(1)-Mg(3) bond lengths are 3.57 Å. Both Sr(1)-Mg(4) bond lengths are 3.66 Å. Both Sr(1)-Mg(5) bond lengths are 3.60 Å. All Sr(1)-Mg(2) bond lengths are 3.46 Å. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(5) atoms to form distorted MgMg10 cuboctahedra that share corners with four equivalent Mg(1)Mg10 cuboctahedra, corners with four equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with eight equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with four equivalent Mg(1)Mg10 cuboctahedra, faces with four equivalent Mg(5)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Sr2Mg10 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.10 Å. Both Mg(1)-Mg(3) bond lengths are 3.18 Å. Both Mg(1)-Mg(4) bond lengths are 3.23 Å. All Mg(1)-Mg(5) bond lengths are 3.28 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to four equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(5) atoms. Both Mg(2)-Mg(2) bond lengths are 3.51 Å. Both Mg(2)-Mg(5) bond lengths are 3.20 Å. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(3), and four equivalent Mg(4) atoms. Both Mg(3)-Mg(3) bond lengths are 3.51 Å. All Mg(3)-Mg(4) bond lengths are 3.29 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with six equivalent Sr(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with three equivalent Sr(1)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(5)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(5)Sr2Mg10 cuboctahedra, faces with four equivalent Mg(4)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(1)Mg10 cuboctahedra. Both Mg(4)-Mg(4) bond lengths are 3.51 Å. Both Mg(4)-Mg(5) bond lengths are 3.13 Å. In the fifth Mg site, Mg(5) is bonded to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(1) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg10 cuboctahedra, corners with six equivalent Sr(1)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(4)Sr2Mg10 cuboctahedra, corners with six equivalent Mg(5)Sr2Mg10 cuboctahedra, edges with three equivalent Sr(1)Sr2Mg10 cuboctahedra, edges with three equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(4)Sr2Mg10 cuboctahedra, faces with four equivalent Mg(1)Mg10 cuboctahedra, and faces with four equivalent Mg(5)Sr2Mg10 cuboctahedra. Both Mg(5)-Mg(5) bond lengths are 3.51 Å.