Sr2EuTa(CuO4)2 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. Eu(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. Ta(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form TaO6 octahedra that share corners with four equivalent Ta(1)O6 octahedra and corners with two equivalent Cu(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 7°. Cu(1) is bonded to one O(1) and four equivalent O(2) atoms to form CuO5 square pyramids that share  a cornercorner with one Ta(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 1°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Sr(1), one Ta(1), and one Cu(1) atom. In the second O site, O(2) is bonded to two equivalent Sr(1), two equivalent Eu(1), and two equivalent Cu(1) atoms to form a mixture of distorted face, corner, and edge-sharing OSr2Eu2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-67°. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Ta(1) atoms.
Sr2EuTa(CuO4)2 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. There are a spread of Sr(1)-O(1) bond distances ranging from 2.72-2.89 Å. All Sr(1)-O(2) bond lengths are 2.78 Å. There are two shorter (2.96 Å) and two longer (3.21 Å) Sr(1)-O(3) bond lengths. Eu(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. All Eu(1)-O(2) bond lengths are 2.51 Å. Ta(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form TaO6 octahedra that share corners with four equivalent Ta(1)O6 octahedra and corners with two equivalent Cu(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 7°. Both Ta(1)-O(1) bond lengths are 1.98 Å. There are two shorter (1.94 Å) and two longer (2.00 Å) Ta(1)-O(3) bond lengths. Cu(1) is bonded to one O(1) and four equivalent O(2) atoms to form CuO5 square pyramids that share  a cornercorner with one Ta(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 1°. The Cu(1)-O(1) bond length is 2.22 Å. All Cu(1)-O(2) bond lengths are 1.97 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Sr(1), one Ta(1), and one Cu(1) atom. In the second O site, O(2) is bonded to two equivalent Sr(1), two equivalent Eu(1), and two equivalent Cu(1) atoms to form a mixture of distorted face, corner, and edge-sharing OSr2Eu2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-67°. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Ta(1) atoms.