Mn4Si4O13 crystallizes in the triclinic P-1 space group. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(6), and two equivalent O(2) atoms. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), one O(4), one O(6), and two equivalent O(1) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  an edgeedge with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. In the third Mn site, Mn(3) is bonded to one O(10), one O(4), one O(7), one O(9), and two equivalent O(8) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Mn(4)O5 trigonal bipyramids,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 52°. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(5), one O(9), and two equivalent O(7) atoms to form distorted MnO5 trigonal bipyramids that share corners with two equivalent Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 61-71°. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(4), one O(5), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, and  an edgeedge with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 54-57°. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(13), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(3)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 60-65°. In the third Si site, Si(3) is bonded to one O(1), one O(11), one O(12), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-67°. In the fourth Si site, Si(4) is bonded to one O(11), one O(13), one O(2), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Mn(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 54-55°. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Mn(2) and one Si(3) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one Si(4) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mn(1), one Mn(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mn(2), one Mn(3), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(4), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Si(2) atom. In the seventh O site, O(7) is bonded to one Mn(3), two equivalent Mn(4), and one Si(4) atom to form distorted edge-sharing OMn3Si tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to two equivalent Mn(3) and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Mn(3), one Mn(4), and one Si(1) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mn(3), one Mn(4), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(4) atom.
Mn4Si4O13 crystallizes in the triclinic P-1 space group. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(6), and two equivalent O(2) atoms. The Mn(1)-O(3) bond length is 2.24 Å. The Mn(1)-O(5) bond length is 2.04 Å. The Mn(1)-O(6) bond length is 2.04 Å. There is one shorter (2.15 Å) and one longer (2.24 Å) Mn(1)-O(2) bond length. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), one O(4), one O(6), and two equivalent O(1) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  an edgeedge with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. The Mn(2)-O(2) bond length is 2.56 Å. The Mn(2)-O(3) bond length is 2.10 Å. The Mn(2)-O(4) bond length is 2.04 Å. The Mn(2)-O(6) bond length is 2.27 Å. There is one shorter (2.10 Å) and one longer (2.14 Å) Mn(2)-O(1) bond length. In the third Mn site, Mn(3) is bonded to one O(10), one O(4), one O(7), one O(9), and two equivalent O(8) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Mn(4)O5 trigonal bipyramids,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 52°. The Mn(3)-O(10) bond length is 2.06 Å. The Mn(3)-O(4) bond length is 2.08 Å. The Mn(3)-O(7) bond length is 2.42 Å. The Mn(3)-O(9) bond length is 2.27 Å. There is one shorter (2.07 Å) and one longer (2.09 Å) Mn(3)-O(8) bond length. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(5), one O(9), and two equivalent O(7) atoms to form distorted MnO5 trigonal bipyramids that share corners with two equivalent Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 61-71°. The Mn(4)-O(10) bond length is 2.13 Å. The Mn(4)-O(5) bond length is 2.09 Å. The Mn(4)-O(9) bond length is 1.99 Å. There is one shorter (2.13 Å) and one longer (2.17 Å) Mn(4)-O(7) bond length. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(4), one O(5), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, and  an edgeedge with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 54-57°. The Si(1)-O(3) bond length is 1.63 Å. The Si(1)-O(4) bond length is 1.67 Å. The Si(1)-O(5) bond length is 1.68 Å. The Si(1)-O(9) bond length is 1.66 Å. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(13), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(3)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 60-65°. The Si(2)-O(10) bond length is 1.62 Å. The Si(2)-O(12) bond length is 1.64 Å. The Si(2)-O(13) bond length is 1.64 Å. The Si(2)-O(6) bond length is 1.64 Å. In the third Si site, Si(3) is bonded to one O(1), one O(11), one O(12), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-67°. The Si(3)-O(1) bond length is 1.64 Å. The Si(3)-O(11) bond length is 1.60 Å. The Si(3)-O(12) bond length is 1.63 Å. The Si(3)-O(8) bond length is 1.64 Å. In the fourth Si site, Si(4) is bonded to one O(11), one O(13), one O(2), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Mn(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 54-55°. The Si(4)-O(11) bond length is 1.61 Å. The Si(4)-O(13) bond length is 1.62 Å. The Si(4)-O(2) bond length is 1.64 Å. The Si(4)-O(7) bond length is 1.66 Å. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Mn(2) and one Si(3) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one Si(4) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mn(1), one Mn(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mn(2), one Mn(3), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(4), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Si(2) atom. In the seventh O site, O(7) is bonded to one Mn(3), two equivalent Mn(4), and one Si(4) atom to form distorted edge-sharing OMn3Si tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to two equivalent Mn(3) and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Mn(3), one Mn(4), and one Si(1) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mn(3), one Mn(4), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(4) atom.