Sr3In11 crystallizes in the orthorhombic Immm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 14-coordinate geometry to two equivalent In(3), two equivalent In(4), four equivalent In(2), and six equivalent In(1) atoms. In the second Sr site, Sr(2) is bonded to four equivalent In(1) and eight equivalent In(2) atoms to form SrIn12 cuboctahedra that share edges with two equivalent In(4)Sr4In8 cuboctahedra and faces with two equivalent Sr(2)In12 cuboctahedra. There are four inequivalent In sites. In the first In site, In(1) is bonded in a 10-coordinate geometry to one Sr(2), three equivalent Sr(1), one In(4), two equivalent In(3), and three equivalent In(2) atoms. In the second In site, In(2) is bonded in a 9-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), one In(2), one In(3), and three equivalent In(1) atoms. In the third In site, In(3) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent In(2), two equivalent In(4), and four equivalent In(1) atoms. In the fourth In site, In(4) is bonded to four equivalent Sr(1), four equivalent In(1), and four equivalent In(3) atoms to form InSr4In8 cuboctahedra that share edges with two equivalent Sr(2)In12 cuboctahedra and faces with two equivalent In(4)Sr4In8 cuboctahedra.
Sr3In11 crystallizes in the orthorhombic Immm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 14-coordinate geometry to two equivalent In(3), two equivalent In(4), four equivalent In(2), and six equivalent In(1) atoms. Both Sr(1)-In(3) bond lengths are 3.53 Å. Both Sr(1)-In(4) bond lengths are 3.62 Å. All Sr(1)-In(2) bond lengths are 3.60 Å. There are four shorter (3.56 Å) and two longer (3.96 Å) Sr(1)-In(1) bond lengths. In the second Sr site, Sr(2) is bonded to four equivalent In(1) and eight equivalent In(2) atoms to form SrIn12 cuboctahedra that share edges with two equivalent In(4)Sr4In8 cuboctahedra and faces with two equivalent Sr(2)In12 cuboctahedra. All Sr(2)-In(1) bond lengths are 3.82 Å. All Sr(2)-In(2) bond lengths are 3.63 Å. There are four inequivalent In sites. In the first In site, In(1) is bonded in a 10-coordinate geometry to one Sr(2), three equivalent Sr(1), one In(4), two equivalent In(3), and three equivalent In(2) atoms. The In(1)-In(4) bond length is 3.33 Å. Both In(1)-In(3) bond lengths are 3.24 Å. There are two shorter (2.97 Å) and one longer (3.00 Å) In(1)-In(2) bond length. In the second In site, In(2) is bonded in a 9-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), one In(2), one In(3), and three equivalent In(1) atoms. The In(2)-In(2) bond length is 2.88 Å. The In(2)-In(3) bond length is 3.03 Å. In the third In site, In(3) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent In(2), two equivalent In(4), and four equivalent In(1) atoms. Both In(3)-In(4) bond lengths are 3.33 Å. In the fourth In site, In(4) is bonded to four equivalent Sr(1), four equivalent In(1), and four equivalent In(3) atoms to form InSr4In8 cuboctahedra that share edges with two equivalent Sr(2)In12 cuboctahedra and faces with two equivalent In(4)Sr4In8 cuboctahedra.