NaTaGeO5 crystallizes in the monoclinic C2/c space group. Na(1) is bonded to one O(1), two equivalent O(3), and four equivalent O(2) atoms to form distorted NaO7 pentagonal bipyramids that share corners with four equivalent Ge(1)O4 tetrahedra, edges with four equivalent Ta(1)O6 octahedra, edges with two equivalent Na(1)O7 pentagonal bipyramids, and  an edgeedge with one Ge(1)O4 tetrahedra. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with four equivalent Ge(1)O4 tetrahedra, and edges with four equivalent Na(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 34°. Ge(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form GeO4 tetrahedra that share corners with four equivalent Ta(1)O6 octahedra, corners with four equivalent Na(1)O7 pentagonal bipyramids, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 36-51°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Na(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Ta(1), and one Ge(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Na(1), one Ta(1), and one Ge(1) atom.
NaTaGeO5 crystallizes in the monoclinic C2/c space group. Na(1) is bonded to one O(1), two equivalent O(3), and four equivalent O(2) atoms to form distorted NaO7 pentagonal bipyramids that share corners with four equivalent Ge(1)O4 tetrahedra, edges with four equivalent Ta(1)O6 octahedra, edges with two equivalent Na(1)O7 pentagonal bipyramids, and  an edgeedge with one Ge(1)O4 tetrahedra. The Na(1)-O(1) bond length is 2.34 Å. Both Na(1)-O(3) bond lengths are 2.51 Å. There are two shorter (2.63 Å) and two longer (2.69 Å) Na(1)-O(2) bond lengths. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with four equivalent Ge(1)O4 tetrahedra, and edges with four equivalent Na(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 34°. Both Ta(1)-O(1) bond lengths are 1.96 Å. Both Ta(1)-O(2) bond lengths are 2.03 Å. Both Ta(1)-O(3) bond lengths are 2.00 Å. Ge(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form GeO4 tetrahedra that share corners with four equivalent Ta(1)O6 octahedra, corners with four equivalent Na(1)O7 pentagonal bipyramids, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 36-51°. Both Ge(1)-O(2) bond lengths are 1.77 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 distorted trigonal non-coplanar geometry to one Na(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Ta(1), and one Ge(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Na(1), one Ta(1), and one Ge(1) atom.