Na2Eu2Ti2O9 crystallizes in the orthorhombic Imm2 space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(5) and four equivalent O(1) atoms. Eu(1) is bonded in a 9-coordinate geometry to two equivalent O(3), two equivalent O(4), and five equivalent O(2) atoms. Ti(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(3), and two equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to four equivalent Na(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to five equivalent Eu(1) atoms. In the third O site, O(3) is bonded to two equivalent Eu(1) and two equivalent Ti(1) atoms to form distorted corner-sharing OEu2Ti2 trigonal pyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a square co-planar geometry to four equivalent Na(1) atoms.
Na2Eu2Ti2O9 crystallizes in the orthorhombic Imm2 space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(5) and four equivalent O(1) atoms. There is one shorter (2.39 Å) and one longer (2.40 Å) Na(1)-O(5) bond length. There are two shorter (2.54 Å) and two longer (2.78 Å) Na(1)-O(1) bond lengths. Eu(1) is bonded in a 9-coordinate geometry to two equivalent O(3), two equivalent O(4), and five equivalent O(2) atoms. Both Eu(1)-O(3) bond lengths are 2.48 Å. Both Eu(1)-O(4) bond lengths are 2.47 Å. There is one shorter (2.28 Å) and four longer (2.66 Å) Eu(1)-O(2) bond lengths. Ti(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(3), and two equivalent O(4) atoms. The Ti(1)-O(1) bond length is 1.75 Å. Both Ti(1)-O(3) bond lengths are 1.94 Å. Both Ti(1)-O(4) bond lengths are 1.93 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to four equivalent Na(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to five equivalent Eu(1) atoms. In the third O site, O(3) is bonded to two equivalent Eu(1) and two equivalent Ti(1) atoms to form distorted corner-sharing OEu2Ti2 trigonal pyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a square co-planar geometry to four equivalent Na(1) atoms.