Sr2Sb3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one Sb(1), one Sb(2), one Sb(3), two equivalent Sb(5), and three equivalent Sb(6) atoms to form a mixture of distorted corner, edge, and face-sharing SrSb8 hexagonal bipyramids. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one Sb(2), one Sb(3), one Sb(6), two equivalent Sb(4), and three equivalent Sb(1) atoms. In the third Sr site, Sr(3) is bonded in a 9-coordinate geometry to one Sb(1), one Sb(3), one Sb(6), two equivalent Sb(2), two equivalent Sb(4), and two equivalent Sb(5) atoms. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one Sb(1), one Sb(4), one Sb(6), two equivalent Sb(2), two equivalent Sb(3), and two equivalent Sb(5) atoms. There are six inequivalent Sb sites. In the first Sb site, Sb(5) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), two equivalent Sr(4), one Sb(4), and one Sb(6) atom. In the second Sb site, Sb(6) is bonded in a 7-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), three equivalent Sr(1), and one Sb(5) atom. In the third Sb site, Sb(1) is bonded in a 7-coordinate geometry to one Sr(1), one Sr(3), one Sr(4), three equivalent Sr(2), and one Sb(2) atom. In the fourth Sb site, Sb(2) is bonded in a 8-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(3), two equivalent Sr(4), one Sb(1), and one Sb(3) atom. In the fifth Sb site, Sb(3) is bonded in a 7-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), two equivalent Sr(4), one Sb(2), and one Sb(4) atom. In the sixth Sb site, Sb(4) is bonded in a 7-coordinate geometry to one Sr(4), two equivalent Sr(2), two equivalent Sr(3), one Sb(3), and one Sb(5) atom.
Sr2Sb3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one Sb(1), one Sb(2), one Sb(3), two equivalent Sb(5), and three equivalent Sb(6) atoms to form a mixture of distorted corner, edge, and face-sharing SrSb8 hexagonal bipyramids. The Sr(1)-Sb(1) bond length is 3.40 Å. The Sr(1)-Sb(2) bond length is 3.40 Å. The Sr(1)-Sb(3) bond length is 3.45 Å. There is one shorter (3.44 Å) and one longer (3.53 Å) Sr(1)-Sb(5) bond length. There are a spread of Sr(1)-Sb(6) bond distances ranging from 3.38-3.63 Å. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one Sb(2), one Sb(3), one Sb(6), two equivalent Sb(4), and three equivalent Sb(1) atoms. The Sr(2)-Sb(2) bond length is 3.54 Å. The Sr(2)-Sb(3) bond length is 3.42 Å. The Sr(2)-Sb(6) bond length is 3.57 Å. There is one shorter (3.39 Å) and one longer (3.52 Å) Sr(2)-Sb(4) bond length. There are a spread of Sr(2)-Sb(1) bond distances ranging from 3.50-3.66 Å. In the third Sr site, Sr(3) is bonded in a 9-coordinate geometry to one Sb(1), one Sb(3), one Sb(6), two equivalent Sb(2), two equivalent Sb(4), and two equivalent Sb(5) atoms. The Sr(3)-Sb(1) bond length is 3.40 Å. The Sr(3)-Sb(3) bond length is 3.38 Å. The Sr(3)-Sb(6) bond length is 3.43 Å. There is one shorter (3.43 Å) and one longer (3.92 Å) Sr(3)-Sb(2) bond length. There is one shorter (3.48 Å) and one longer (3.80 Å) Sr(3)-Sb(4) bond length. There is one shorter (3.48 Å) and one longer (3.60 Å) Sr(3)-Sb(5) bond length. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one Sb(1), one Sb(4), one Sb(6), two equivalent Sb(2), two equivalent Sb(3), and two equivalent Sb(5) atoms. The Sr(4)-Sb(1) bond length is 3.44 Å. The Sr(4)-Sb(4) bond length is 3.35 Å. The Sr(4)-Sb(6) bond length is 3.39 Å. Both Sr(4)-Sb(2) bond lengths are 3.56 Å. There is one shorter (3.43 Å) and one longer (3.79 Å) Sr(4)-Sb(3) bond length. There is one shorter (3.44 Å) and one longer (3.92 Å) Sr(4)-Sb(5) bond length. There are six inequivalent Sb sites. In the first Sb site, Sb(5) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), two equivalent Sr(4), one Sb(4), and one Sb(6) atom. The Sb(5)-Sb(4) bond length is 2.90 Å. The Sb(5)-Sb(6) bond length is 2.91 Å. In the second Sb site, Sb(6) is bonded in a 7-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), three equivalent Sr(1), and one Sb(5) atom. In the third Sb site, Sb(1) is bonded in a 7-coordinate geometry to one Sr(1), one Sr(3), one Sr(4), three equivalent Sr(2), and one Sb(2) atom. The Sb(1)-Sb(2) bond length is 2.93 Å. In the fourth Sb site, Sb(2) is bonded in a 8-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(3), two equivalent Sr(4), one Sb(1), and one Sb(3) atom. The Sb(2)-Sb(3) bond length is 2.90 Å. In the fifth Sb site, Sb(3) is bonded in a 7-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), two equivalent Sr(4), one Sb(2), and one Sb(4) atom. The Sb(3)-Sb(4) bond length is 3.02 Å. In the sixth Sb site, Sb(4) is bonded in a 7-coordinate geometry to one Sr(4), two equivalent Sr(2), two equivalent Sr(3), one Sb(3), and one Sb(5) atom.