Na2MnInSi2O9 crystallizes in the orthorhombic Cmc2_1 space group. Na(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), and three equivalent O(4) atoms. Mn(1) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one In(1)O6 pentagonal pyramid, corners with four equivalent Si(1)O4 tetrahedra, and  a faceface with one In(1)O6 pentagonal pyramid. In(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted InO6 pentagonal pyramids that share corners with two equivalent In(1)O6 pentagonal pyramids, corners with four equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mn(1)O5 trigonal bipyramid, and  a faceface with one Mn(1)O5 trigonal bipyramid. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent In(1)O6 pentagonal pyramids and corners with two equivalent Mn(1)O5 trigonal bipyramids. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one In(1), and one Si(1) atom. In the second O site, O(4) is bonded in a 4-coordinate geometry to three equivalent Na(1) and one Si(1) atom. In the third O site, O(5) is bonded in a 3-coordinate geometry to one Mn(1) and two equivalent In(1) atoms. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to one Mn(1) and one Si(1) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Mn(1), one In(1), and one Si(1) atom.
Na2MnInSi2O9 crystallizes in the orthorhombic Cmc2_1 space group. Na(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), and three equivalent O(4) atoms. The Na(1)-O(2) bond length is 2.82 Å. The Na(1)-O(3) bond length is 2.37 Å. There are a spread of Na(1)-O(4) bond distances ranging from 2.33-2.87 Å. Mn(1) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one In(1)O6 pentagonal pyramid, corners with four equivalent Si(1)O4 tetrahedra, and  a faceface with one In(1)O6 pentagonal pyramid. The Mn(1)-O(5) bond length is 1.81 Å. Both Mn(1)-O(1) bond lengths are 1.82 Å. Both Mn(1)-O(2) bond lengths are 1.97 Å. In(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted InO6 pentagonal pyramids that share corners with two equivalent In(1)O6 pentagonal pyramids, corners with four equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mn(1)O5 trigonal bipyramid, and  a faceface with one Mn(1)O5 trigonal bipyramid. Both In(1)-O(2) bond lengths are 2.34 Å. Both In(1)-O(3) bond lengths are 2.10 Å. There is one shorter (2.11 Å) and one longer (2.19 Å) In(1)-O(5) bond length. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent In(1)O6 pentagonal pyramids and corners with two equivalent Mn(1)O5 trigonal bipyramids. The Si(1)-O(1) bond length is 1.65 Å. The Si(1)-O(2) bond length is 1.68 Å. The Si(1)-O(3) bond length is 1.64 Å. The Si(1)-O(4) bond length is 1.61 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one In(1), and one Si(1) atom. In the second O site, O(4) is bonded in a 4-coordinate geometry to three equivalent Na(1) and one Si(1) atom. In the third O site, O(5) is bonded in a 3-coordinate geometry to one Mn(1) and two equivalent In(1) atoms. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to one Mn(1) and one Si(1) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Mn(1), one In(1), and one Si(1) atom.