Ba2FeGe2O7 crystallizes in the tetragonal P-42_1m space group. Ba(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. Fe(1) is bonded to four equivalent O(3) atoms to form FeO4 tetrahedra that share corners with four equivalent Ge(1)O4 tetrahedra. Ge(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form GeO4 tetrahedra that share  a cornercorner with one Ge(1)O4 tetrahedra and corners with two equivalent Fe(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Ge(1) atoms. In the second O site, O(2) is bonded to three equivalent Ba(1) and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OBa3Ge tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Fe(1), and one Ge(1) atom.
Ba2FeGe2O7 crystallizes in the tetragonal P-42_1m space group. Ba(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. The Ba(1)-O(1) bond length is 2.79 Å. There is one shorter (2.70 Å) and two longer (2.82 Å) Ba(1)-O(2) bond lengths. There are two shorter (2.79 Å) and two longer (3.05 Å) Ba(1)-O(3) bond lengths. Fe(1) is bonded to four equivalent O(3) atoms to form FeO4 tetrahedra that share corners with four equivalent Ge(1)O4 tetrahedra. All Fe(1)-O(3) bond lengths are 1.98 Å. Ge(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form GeO4 tetrahedra that share  a cornercorner with one Ge(1)O4 tetrahedra and corners with two equivalent Fe(1)O4 tetrahedra. The Ge(1)-O(1) bond length is 1.80 Å. The Ge(1)-O(2) bond length is 1.73 Å. Both Ge(1)-O(3) bond lengths are 1.76 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Ge(1) atoms. In the second O site, O(2) is bonded to three equivalent Ba(1) and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OBa3Ge tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Fe(1), and one Ge(1) atom.