The crystal structure described by Mn3SiN4 is Enargite structured and crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one N(2), one N(3), and three equivalent N(1) atoms to form distorted MnN5 trigonal bipyramids that share corners with three equivalent Si(1)N4 tetrahedra, corners with two equivalent Mn(2)N5 trigonal bipyramids, corners with four equivalent Mn(1)N5 trigonal bipyramids,  an edgeedge with one Si(1)N4 tetrahedra, edges with two equivalent Mn(1)N5 trigonal bipyramids, and edges with two equivalent Mn(2)N5 trigonal bipyramids. In the second Mn site, Mn(2) is bonded to one N(3), two equivalent N(1), and two equivalent N(2) atoms to form distorted MnN5 trigonal bipyramids that share corners with three equivalent Si(1)N4 tetrahedra, corners with two equivalent Mn(2)N5 trigonal bipyramids, corners with four equivalent Mn(1)N5 trigonal bipyramids,  an edgeedge with one Si(1)N4 tetrahedra, and edges with four equivalent Mn(1)N5 trigonal bipyramids. Si(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form SiN4 tetrahedra that share corners with three equivalent Mn(2)N5 trigonal bipyramids, corners with six equivalent Mn(1)N5 trigonal bipyramids,  an edgeedge with one Mn(2)N5 trigonal bipyramid, and edges with two equivalent Mn(1)N5 trigonal bipyramids. There are three inequivalent N sites. In the first N site, N(1) is bonded to one Mn(2), three equivalent Mn(1), and one Si(1) atom to form distorted NMn4Si trigonal bipyramids that share corners with two equivalent N(2)Mn4Si trigonal bipyramids, corners with four equivalent N(1)Mn4Si trigonal bipyramids, corners with three equivalent N(3)Mn3Si trigonal pyramids, edges with two equivalent N(1)Mn4Si trigonal bipyramids, edges with two equivalent N(2)Mn4Si trigonal bipyramids, and  an edgeedge with one N(3)Mn3Si trigonal pyramid. In the second N site, N(2) is bonded to two equivalent Mn(1), two equivalent Mn(2), and one Si(1) atom to form distorted NMn4Si trigonal bipyramids that share corners with two equivalent N(2)Mn4Si trigonal bipyramids, corners with four equivalent N(1)Mn4Si trigonal bipyramids, corners with three equivalent N(3)Mn3Si trigonal pyramids, edges with four equivalent N(1)Mn4Si trigonal bipyramids, and  an edgeedge with one N(3)Mn3Si trigonal pyramid. In the third N site, N(3) is bonded to one Mn(2), two equivalent Mn(1), and one Si(1) atom to form a mixture of edge and corner-sharing NMn3Si trigonal pyramids. is represented by the CIF card [CIF]
data_Mn3SiN4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.610
_cell_length_b   5.636
_cell_length_c   4.480
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   166.910
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mn  Mn0  1  0.778  0.655  0.394  1.0
  Mn  Mn1  1  0.222  0.655  0.394  1.0
  Mn  Mn2  1  0.722  0.345  0.894  1.0
  Mn  Mn3  1  0.278  0.345  0.894  1.0
  Mn  Mn4  1  0.500  0.782  0.901  1.0
  Mn  Mn5  1  0.000  0.218  0.401  1.0
  Si  Si6  1  0.000  0.865  0.946  1.0
  Si  Si7  1  0.500  0.135  0.446  1.0
  N  N8  1  0.714  0.307  0.375  1.0
  N  N9  1  0.286  0.307  0.375  1.0
  N  N10  1  0.786  0.693  0.875  1.0
  N  N11  1  0.214  0.693  0.875  1.0
  N  N12  1  0.500  0.833  0.361  1.0
  N  N13  1  0.000  0.167  0.861  1.0
  N  N14  1  0.500  0.124  0.840  1.0
  N  N15  1  0.000  0.876  0.340  1.0
[/CIF]
.
The crystal structure described by Mn3SiN4 is Enargite structured and crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one N(2), one N(3), and three equivalent N(1) atoms to form distorted MnN5 trigonal bipyramids that share corners with three equivalent Si(1)N4 tetrahedra, corners with two equivalent Mn(2)N5 trigonal bipyramids, corners with four equivalent Mn(1)N5 trigonal bipyramids,  an edgeedge with one Si(1)N4 tetrahedra, edges with two equivalent Mn(1)N5 trigonal bipyramids, and edges with two equivalent Mn(2)N5 trigonal bipyramids. In the second Mn site, Mn(2) is bonded to one N(3), two equivalent N(1), and two equivalent N(2) atoms to form distorted MnN5 trigonal bipyramids that share corners with three equivalent Si(1)N4 tetrahedra, corners with two equivalent Mn(2)N5 trigonal bipyramids, corners with four equivalent Mn(1)N5 trigonal bipyramids,  an edgeedge with one Si(1)N4 tetrahedra, and edges with four equivalent Mn(1)N5 trigonal bipyramids. Si(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form SiN4 tetrahedra that share corners with three equivalent Mn(2)N5 trigonal bipyramids, corners with six equivalent Mn(1)N5 trigonal bipyramids,  an edgeedge with one Mn(2)N5 trigonal bipyramid, and edges with two equivalent Mn(1)N5 trigonal bipyramids. There are three inequivalent N sites. In the first N site, N(1) is bonded to one Mn(2), three equivalent Mn(1), and one Si(1) atom to form distorted NMn4Si trigonal bipyramids that share corners with two equivalent N(2)Mn4Si trigonal bipyramids, corners with four equivalent N(1)Mn4Si trigonal bipyramids, corners with three equivalent N(3)Mn3Si trigonal pyramids, edges with two equivalent N(1)Mn4Si trigonal bipyramids, edges with two equivalent N(2)Mn4Si trigonal bipyramids, and  an edgeedge with one N(3)Mn3Si trigonal pyramid. In the second N site, N(2) is bonded to two equivalent Mn(1), two equivalent Mn(2), and one Si(1) atom to form distorted NMn4Si trigonal bipyramids that share corners with two equivalent N(2)Mn4Si trigonal bipyramids, corners with four equivalent N(1)Mn4Si trigonal bipyramids, corners with three equivalent N(3)Mn3Si trigonal pyramids, edges with four equivalent N(1)Mn4Si trigonal bipyramids, and  an edgeedge with one N(3)Mn3Si trigonal pyramid. In the third N site, N(3) is bonded to one Mn(2), two equivalent Mn(1), and one Si(1) atom to form a mixture of edge and corner-sharing NMn3Si trigonal pyramids. is represented by the CIF card [CIF]
data_Mn3SiN4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.610
_cell_length_b   5.636
_cell_length_c   4.480
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   166.910
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mn  Mn0  1  0.778  0.655  0.394  1.0
  Mn  Mn1  1  0.222  0.655  0.394  1.0
  Mn  Mn2  1  0.722  0.345  0.894  1.0
  Mn  Mn3  1  0.278  0.345  0.894  1.0
  Mn  Mn4  1  0.500  0.782  0.901  1.0
  Mn  Mn5  1  0.000  0.218  0.401  1.0
  Si  Si6  1  0.000  0.865  0.946  1.0
  Si  Si7  1  0.500  0.135  0.446  1.0
  N  N8  1  0.714  0.307  0.375  1.0
  N  N9  1  0.286  0.307  0.375  1.0
  N  N10  1  0.786  0.693  0.875  1.0
  N  N11  1  0.214  0.693  0.875  1.0
  N  N12  1  0.500  0.833  0.361  1.0
  N  N13  1  0.000  0.167  0.861  1.0
  N  N14  1  0.500  0.124  0.840  1.0
  N  N15  1  0.000  0.876  0.340  1.0
[/CIF]
.