Ca5Sb3 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent Sb(2) and three equivalent Sb(1) atoms. In the second Ca site, Ca(2) is bonded to one Sb(2) and four equivalent Sb(1) atoms to form a mixture of distorted face, corner, and edge-sharing CaSb5 square pyramids. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one Sb(2) and four equivalent Sb(1) atoms. In the fourth Ca site, Ca(4) is bonded to one Sb(2) and four equivalent Sb(1) atoms to form a mixture of distorted face, corner, and edge-sharing CaSb5 square pyramids. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 9-coordinate geometry to two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and three equivalent Ca(1) atoms. In the second Sb site, Sb(2) is bonded in a 7-coordinate geometry to one Ca(2), one Ca(3), one Ca(4), and four equivalent Ca(1) atoms.
Ca5Sb3 crystallizes in the orthorhombic Pnma space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent Sb(2) and three equivalent Sb(1) atoms. There is one shorter (3.06 Å) and one longer (3.21 Å) Ca(1)-Sb(2) bond length. There are a spread of Ca(1)-Sb(1) bond distances ranging from 3.33-3.76 Å. In the second Ca site, Ca(2) is bonded to one Sb(2) and four equivalent Sb(1) atoms to form a mixture of distorted face, corner, and edge-sharing CaSb5 square pyramids. The Ca(2)-Sb(2) bond length is 3.19 Å. There are two shorter (3.30 Å) and two longer (3.37 Å) Ca(2)-Sb(1) bond lengths. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one Sb(2) and four equivalent Sb(1) atoms. The Ca(3)-Sb(2) bond length is 3.09 Å. There are two shorter (3.31 Å) and two longer (3.44 Å) Ca(3)-Sb(1) bond lengths. In the fourth Ca site, Ca(4) is bonded to one Sb(2) and four equivalent Sb(1) atoms to form a mixture of distorted face, corner, and edge-sharing CaSb5 square pyramids. The Ca(4)-Sb(2) bond length is 3.23 Å. There are two shorter (3.27 Å) and two longer (3.28 Å) Ca(4)-Sb(1) bond lengths. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 9-coordinate geometry to two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and three equivalent Ca(1) atoms. In the second Sb site, Sb(2) is bonded in a 7-coordinate geometry to one Ca(2), one Ca(3), one Ca(4), and four equivalent Ca(1) atoms.