Ca5Au2 crystallizes in the triclinic P-1 space group. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 3-coordinate geometry to one Au(1) and two equivalent Au(2) atoms. In the second Ca site, Ca(2) is bonded in a 3-coordinate geometry to one Au(2) and two equivalent Au(1) atoms. In the third Ca site, Ca(3) is bonded to two equivalent Au(1) and two equivalent Au(2) atoms to form distorted edge-sharing CaAu4 tetrahedra. In the fourth Ca site, Ca(4) is bonded in a 2-coordinate geometry to one Au(2) and two equivalent Au(1) atoms. In the fifth Ca site, Ca(5) is bonded in a 2-coordinate geometry to one Au(1) and two equivalent Au(2) atoms. There are two inequivalent Au sites. In the first Au site, Au(1) is bonded in a 8-coordinate geometry to one Ca(1), one Ca(5), two equivalent Ca(2), two equivalent Ca(3), and two equivalent Ca(4) atoms. In the second Au site, Au(2) is bonded in a 8-coordinate geometry to one Ca(2), one Ca(4), two equivalent Ca(1), two equivalent Ca(3), and two equivalent Ca(5) atoms.
Ca5Au2 crystallizes in the triclinic P-1 space group. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 3-coordinate geometry to one Au(1) and two equivalent Au(2) atoms. The Ca(1)-Au(1) bond length is 3.10 Å. There is one shorter (3.04 Å) and one longer (3.23 Å) Ca(1)-Au(2) bond length. In the second Ca site, Ca(2) is bonded in a 3-coordinate geometry to one Au(2) and two equivalent Au(1) atoms. The Ca(2)-Au(2) bond length is 3.11 Å. There is one shorter (3.04 Å) and one longer (3.23 Å) Ca(2)-Au(1) bond length. In the third Ca site, Ca(3) is bonded to two equivalent Au(1) and two equivalent Au(2) atoms to form distorted edge-sharing CaAu4 tetrahedra. There is one shorter (3.10 Å) and one longer (3.11 Å) Ca(3)-Au(1) bond length. Both Ca(3)-Au(2) bond lengths are 3.10 Å. In the fourth Ca site, Ca(4) is bonded in a 2-coordinate geometry to one Au(2) and two equivalent Au(1) atoms. The Ca(4)-Au(2) bond length is 2.98 Å. There is one shorter (3.02 Å) and one longer (3.62 Å) Ca(4)-Au(1) bond length. In the fifth Ca site, Ca(5) is bonded in a 2-coordinate geometry to one Au(1) and two equivalent Au(2) atoms. The Ca(5)-Au(1) bond length is 2.98 Å. There is one shorter (3.02 Å) and one longer (3.63 Å) Ca(5)-Au(2) bond length. There are two inequivalent Au sites. In the first Au site, Au(1) is bonded in a 8-coordinate geometry to one Ca(1), one Ca(5), two equivalent Ca(2), two equivalent Ca(3), and two equivalent Ca(4) atoms. In the second Au site, Au(2) is bonded in a 8-coordinate geometry to one Ca(2), one Ca(4), two equivalent Ca(1), two equivalent Ca(3), and two equivalent Ca(5) atoms.