BaSrPb6 crystallizes in the trigonal P3m1 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent Pb(1), three equivalent Pb(4), and six equivalent Pb(5) atoms to form BaPb12 cuboctahedra that share corners with three equivalent Sr(1)Pb12 cuboctahedra, corners with three equivalent Sr(2)Pb12 cuboctahedra, corners with six equivalent Ba(1)Pb12 cuboctahedra, faces with three equivalent Ba(3)Pb12 cuboctahedra, and faces with three equivalent Sr(3)Pb12 cuboctahedra. In the second Ba site, Ba(2) is bonded to three equivalent Pb(2), three equivalent Pb(3), and six equivalent Pb(6) atoms to form BaPb12 cuboctahedra that share corners with three equivalent Ba(3)Pb12 cuboctahedra, corners with three equivalent Sr(3)Pb12 cuboctahedra, corners with six equivalent Ba(2)Pb12 cuboctahedra, faces with three equivalent Sr(1)Pb12 cuboctahedra, and faces with three equivalent Sr(2)Pb12 cuboctahedra. In the third Ba site, Ba(3) is bonded to three equivalent Pb(2), three equivalent Pb(5), and six equivalent Pb(1) atoms to form BaPb12 cuboctahedra that share corners with three equivalent Ba(2)Pb12 cuboctahedra, corners with six equivalent Ba(3)Pb12 cuboctahedra,  a faceface with one Sr(3)Pb12 cuboctahedra, faces with three equivalent Ba(1)Pb12 cuboctahedra, and faces with three equivalent Sr(1)Pb12 cuboctahedra. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to three equivalent Pb(1), three equivalent Pb(6), and six equivalent Pb(2) atoms to form SrPb12 cuboctahedra that share corners with three equivalent Ba(1)Pb12 cuboctahedra, corners with six equivalent Sr(1)Pb12 cuboctahedra,  a faceface with one Sr(2)Pb12 cuboctahedra, faces with three equivalent Ba(2)Pb12 cuboctahedra, and faces with three equivalent Ba(3)Pb12 cuboctahedra. In the second Sr site, Sr(2) is bonded to three equivalent Pb(4), three equivalent Pb(6), and six equivalent Pb(3) atoms to form SrPb12 cuboctahedra that share corners with three equivalent Ba(1)Pb12 cuboctahedra, corners with six equivalent Sr(2)Pb12 cuboctahedra,  a faceface with one Sr(1)Pb12 cuboctahedra, faces with three equivalent Ba(2)Pb12 cuboctahedra, and faces with three equivalent Sr(3)Pb12 cuboctahedra. In the third Sr site, Sr(3) is bonded to three equivalent Pb(3), three equivalent Pb(5), and six equivalent Pb(4) atoms to form SrPb12 cuboctahedra that share corners with three equivalent Ba(2)Pb12 cuboctahedra, corners with six equivalent Sr(3)Pb12 cuboctahedra,  a faceface with one Ba(3)Pb12 cuboctahedra, faces with three equivalent Ba(1)Pb12 cuboctahedra, and faces with three equivalent Sr(2)Pb12 cuboctahedra. There are six inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a distorted square co-planar geometry to one Ba(1), two equivalent Ba(3), and one Sr(1) atom. In the second Pb site, Pb(2) is bonded in a distorted square co-planar geometry to one Ba(2), one Ba(3), and two equivalent Sr(1) atoms. In the third Pb site, Pb(3) is bonded in a distorted square co-planar geometry to one Ba(2), one Sr(3), and two equivalent Sr(2) atoms. In the fourth Pb site, Pb(4) is bonded in a distorted square co-planar geometry to one Ba(1), one Sr(2), and two equivalent Sr(3) atoms. In the fifth Pb site, Pb(5) is bonded in a 4-coordinate geometry to one Ba(3), two equivalent Ba(1), and one Sr(3) atom. In the sixth Pb site, Pb(6) is bonded in a 4-coordinate geometry to two equivalent Ba(2), one Sr(1), and one Sr(2) atom.
BaSrPb6 crystallizes in the trigonal P3m1 space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent Pb(1), three equivalent Pb(4), and six equivalent Pb(5) atoms to form BaPb12 cuboctahedra that share corners with three equivalent Sr(1)Pb12 cuboctahedra, corners with three equivalent Sr(2)Pb12 cuboctahedra, corners with six equivalent Ba(1)Pb12 cuboctahedra, faces with three equivalent Ba(3)Pb12 cuboctahedra, and faces with three equivalent Sr(3)Pb12 cuboctahedra. All Ba(1)-Pb(1) bond lengths are 3.65 Å. All Ba(1)-Pb(4) bond lengths are 3.64 Å. All Ba(1)-Pb(5) bond lengths are 3.64 Å. In the second Ba site, Ba(2) is bonded to three equivalent Pb(2), three equivalent Pb(3), and six equivalent Pb(6) atoms to form BaPb12 cuboctahedra that share corners with three equivalent Ba(3)Pb12 cuboctahedra, corners with three equivalent Sr(3)Pb12 cuboctahedra, corners with six equivalent Ba(2)Pb12 cuboctahedra, faces with three equivalent Sr(1)Pb12 cuboctahedra, and faces with three equivalent Sr(2)Pb12 cuboctahedra. All Ba(2)-Pb(2) bond lengths are 3.63 Å. All Ba(2)-Pb(3) bond lengths are 3.65 Å. All Ba(2)-Pb(6) bond lengths are 3.64 Å. In the third Ba site, Ba(3) is bonded to three equivalent Pb(2), three equivalent Pb(5), and six equivalent Pb(1) atoms to form BaPb12 cuboctahedra that share corners with three equivalent Ba(2)Pb12 cuboctahedra, corners with six equivalent Ba(3)Pb12 cuboctahedra,  a faceface with one Sr(3)Pb12 cuboctahedra, faces with three equivalent Ba(1)Pb12 cuboctahedra, and faces with three equivalent Sr(1)Pb12 cuboctahedra. All Ba(3)-Pb(2) bond lengths are 3.65 Å. All Ba(3)-Pb(5) bond lengths are 3.67 Å. All Ba(3)-Pb(1) bond lengths are 3.63 Å. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to three equivalent Pb(1), three equivalent Pb(6), and six equivalent Pb(2) atoms to form SrPb12 cuboctahedra that share corners with three equivalent Ba(1)Pb12 cuboctahedra, corners with six equivalent Sr(1)Pb12 cuboctahedra,  a faceface with one Sr(2)Pb12 cuboctahedra, faces with three equivalent Ba(2)Pb12 cuboctahedra, and faces with three equivalent Ba(3)Pb12 cuboctahedra. All Sr(1)-Pb(1) bond lengths are 3.63 Å. All Sr(1)-Pb(6) bond lengths are 3.65 Å. All Sr(1)-Pb(2) bond lengths are 3.63 Å. In the second Sr site, Sr(2) is bonded to three equivalent Pb(4), three equivalent Pb(6), and six equivalent Pb(3) atoms to form SrPb12 cuboctahedra that share corners with three equivalent Ba(1)Pb12 cuboctahedra, corners with six equivalent Sr(2)Pb12 cuboctahedra,  a faceface with one Sr(1)Pb12 cuboctahedra, faces with three equivalent Ba(2)Pb12 cuboctahedra, and faces with three equivalent Sr(3)Pb12 cuboctahedra. All Sr(2)-Pb(4) bond lengths are 3.63 Å. All Sr(2)-Pb(6) bond lengths are 3.65 Å. All Sr(2)-Pb(3) bond lengths are 3.63 Å. In the third Sr site, Sr(3) is bonded to three equivalent Pb(3), three equivalent Pb(5), and six equivalent Pb(4) atoms to form SrPb12 cuboctahedra that share corners with three equivalent Ba(2)Pb12 cuboctahedra, corners with six equivalent Sr(3)Pb12 cuboctahedra,  a faceface with one Ba(3)Pb12 cuboctahedra, faces with three equivalent Ba(1)Pb12 cuboctahedra, and faces with three equivalent Sr(2)Pb12 cuboctahedra. All Sr(3)-Pb(3) bond lengths are 3.63 Å. All Sr(3)-Pb(5) bond lengths are 3.64 Å. All Sr(3)-Pb(4) bond lengths are 3.63 Å. There are six inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a distorted square co-planar geometry to one Ba(1), two equivalent Ba(3), and one Sr(1) atom. In the second Pb site, Pb(2) is bonded in a distorted square co-planar geometry to one Ba(2), one Ba(3), and two equivalent Sr(1) atoms. In the third Pb site, Pb(3) is bonded in a distorted square co-planar geometry to one Ba(2), one Sr(3), and two equivalent Sr(2) atoms. In the fourth Pb site, Pb(4) is bonded in a distorted square co-planar geometry to one Ba(1), one Sr(2), and two equivalent Sr(3) atoms. In the fifth Pb site, Pb(5) is bonded in a 4-coordinate geometry to one Ba(3), two equivalent Ba(1), and one Sr(3) atom. In the sixth Pb site, Pb(6) is bonded in a 4-coordinate geometry to two equivalent Ba(2), one Sr(1), and one Sr(2) atom.