CaEu2O3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. Ca(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CaO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Eu(1)O6 octahedra, corners with two equivalent Eu(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with five equivalent Eu(1)O6 octahedra, and edges with five equivalent Eu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form EuO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Eu(1)O6 octahedra, corners with two equivalent Eu(2)O6 octahedra, edges with two equivalent Eu(1)O6 octahedra, edges with five equivalent Ca(1)O6 octahedra, and edges with five equivalent Eu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second Eu site, Eu(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form EuO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Eu(1)O6 octahedra, corners with two equivalent Eu(2)O6 octahedra, edges with two equivalent Eu(2)O6 octahedra, edges with five equivalent Ca(1)O6 octahedra, and edges with five equivalent Eu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), two equivalent Eu(1), and two equivalent Eu(2) atoms to form a mixture of corner and edge-sharing OCa2Eu4 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second O site, O(2) is bonded to two equivalent Ca(1), two equivalent Eu(1), and two equivalent Eu(2) atoms to form a mixture of corner and edge-sharing OCa2Eu4 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.
CaEu2O3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. Ca(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CaO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Eu(1)O6 octahedra, corners with two equivalent Eu(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with five equivalent Eu(1)O6 octahedra, and edges with five equivalent Eu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. Both Ca(1)-O(2) bond lengths are 2.52 Å. There are two shorter (2.45 Å) and two longer (2.46 Å) Ca(1)-O(1) bond lengths. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form EuO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Eu(1)O6 octahedra, corners with two equivalent Eu(2)O6 octahedra, edges with two equivalent Eu(1)O6 octahedra, edges with five equivalent Ca(1)O6 octahedra, and edges with five equivalent Eu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Both Eu(1)-O(2) bond lengths are 2.50 Å. There are two shorter (2.51 Å) and two longer (2.57 Å) Eu(1)-O(1) bond lengths. In the second Eu site, Eu(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form EuO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Eu(1)O6 octahedra, corners with two equivalent Eu(2)O6 octahedra, edges with two equivalent Eu(2)O6 octahedra, edges with five equivalent Ca(1)O6 octahedra, and edges with five equivalent Eu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Both Eu(2)-O(2) bond lengths are 2.51 Å. There are two shorter (2.51 Å) and two longer (2.55 Å) Eu(2)-O(1) bond lengths. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), two equivalent Eu(1), and two equivalent Eu(2) atoms to form a mixture of corner and edge-sharing OCa2Eu4 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second O site, O(2) is bonded to two equivalent Ca(1), two equivalent Eu(1), and two equivalent Eu(2) atoms to form a mixture of corner and edge-sharing OCa2Eu4 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.