The compound described by Eu2SiN3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 5-coordinate geometry to two equivalent N(3) and three equivalent N(1) atoms. In the second Eu site, Eu(2) is bonded to two equivalent N(1), two equivalent N(2), and three equivalent N(3) atoms to form distorted EuN7 pentagonal bipyramids that share corners with four equivalent Eu(2)N7 pentagonal bipyramids,  a cornercorner with one Si(1)N4 tetrahedra, edges with three equivalent Eu(2)N7 pentagonal bipyramids, and edges with four equivalent Si(1)N4 tetrahedra. Si(1) is bonded to one N(1), one N(3), and two equivalent N(2) atoms to form SiN4 tetrahedra that share  a cornercorner with one Eu(2)N7 pentagonal bipyramid, corners with two equivalent Si(1)N4 tetrahedra, and edges with four equivalent Eu(2)N7 pentagonal bipyramids. There are three inequivalent N sites. In the first N site, N(3) is bonded to two equivalent Eu(1), three equivalent Eu(2), and one Si(1) atom to form a mixture of distorted edge and corner-sharing NEu5Si octahedra. The corner-sharing octahedral tilt angles range from 17-56°. In the second N site, N(1) is bonded to two equivalent Eu(2), three equivalent Eu(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing NEu5Si octahedra. The corner-sharing octahedral tilt angles range from 14-56°. In the third N site, N(2) is bonded in a distorted bent 150 degrees geometry to two equivalent Eu(2) and two equivalent Si(1) atoms. is represented by the CIF file [CIF]
data_Eu2SiN3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.964
_cell_length_b   5.964
_cell_length_c   11.678
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   125.893
_symmetry_Int_Tables_number   1
_cell_volume   336.469
_cell_formula_units_Z   4
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
  Eu  Eu0  1  0.052  0.948  0.856  1.0
  Eu  Eu1  1  0.948  0.052  0.144  1.0
  Eu  Eu2  1  0.448  0.552  0.356  1.0
  Eu  Eu3  1  0.552  0.448  0.644  1.0
  Eu  Eu4  1  0.641  0.359  0.075  1.0
  Eu  Eu5  1  0.359  0.641  0.925  1.0
  Eu  Eu6  1  0.859  0.141  0.575  1.0
  Eu  Eu7  1  0.141  0.859  0.425  1.0
  Si  Si8  1  0.743  0.257  0.835  1.0
  Si  Si9  1  0.257  0.743  0.165  1.0
  Si  Si10  1  0.757  0.243  0.335  1.0
  Si  Si11  1  0.243  0.757  0.665  1.0
  N  N12  1  0.582  0.418  0.866  1.0
  N  N13  1  0.418  0.582  0.134  1.0
  N  N14  1  0.918  0.082  0.366  1.0
  N  N15  1  0.082  0.918  0.634  1.0
  N  N16  1  0.530  0.970  0.750  1.0
  N  N17  1  0.970  0.530  0.250  1.0
  N  N18  1  0.470  0.030  0.250  1.0
  N  N19  1  0.030  0.470  0.750  1.0
  N  N20  1  0.842  0.158  0.954  1.0
  N  N21  1  0.158  0.842  0.046  1.0
  N  N22  1  0.658  0.342  0.454  1.0
  N  N23  1  0.342  0.658  0.546  1.0
[/CIF]
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The compound described by Eu2SiN3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 5-coordinate geometry to two equivalent N(3) and three equivalent N(1) atoms. In the second Eu site, Eu(2) is bonded to two equivalent N(1), two equivalent N(2), and three equivalent N(3) atoms to form distorted EuN7 pentagonal bipyramids that share corners with four equivalent Eu(2)N7 pentagonal bipyramids,  a cornercorner with one Si(1)N4 tetrahedra, edges with three equivalent Eu(2)N7 pentagonal bipyramids, and edges with four equivalent Si(1)N4 tetrahedra. Si(1) is bonded to one N(1), one N(3), and two equivalent N(2) atoms to form SiN4 tetrahedra that share  a cornercorner with one Eu(2)N7 pentagonal bipyramid, corners with two equivalent Si(1)N4 tetrahedra, and edges with four equivalent Eu(2)N7 pentagonal bipyramids. There are three inequivalent N sites. In the first N site, N(3) is bonded to two equivalent Eu(1), three equivalent Eu(2), and one Si(1) atom to form a mixture of distorted edge and corner-sharing NEu5Si octahedra. The corner-sharing octahedral tilt angles range from 17-56°. In the second N site, N(1) is bonded to two equivalent Eu(2), three equivalent Eu(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing NEu5Si octahedra. The corner-sharing octahedral tilt angles range from 14-56°. In the third N site, N(2) is bonded in a distorted bent 150 degrees geometry to two equivalent Eu(2) and two equivalent Si(1) atoms. is represented by the CIF file [CIF]
data_Eu2SiN3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.964
_cell_length_b   5.964
_cell_length_c   11.678
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   125.893
_symmetry_Int_Tables_number   1
_cell_volume   336.469
_cell_formula_units_Z   4
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
  Eu  Eu0  1  0.052  0.948  0.856  1.0
  Eu  Eu1  1  0.948  0.052  0.144  1.0
  Eu  Eu2  1  0.448  0.552  0.356  1.0
  Eu  Eu3  1  0.552  0.448  0.644  1.0
  Eu  Eu4  1  0.641  0.359  0.075  1.0
  Eu  Eu5  1  0.359  0.641  0.925  1.0
  Eu  Eu6  1  0.859  0.141  0.575  1.0
  Eu  Eu7  1  0.141  0.859  0.425  1.0
  Si  Si8  1  0.743  0.257  0.835  1.0
  Si  Si9  1  0.257  0.743  0.165  1.0
  Si  Si10  1  0.757  0.243  0.335  1.0
  Si  Si11  1  0.243  0.757  0.665  1.0
  N  N12  1  0.582  0.418  0.866  1.0
  N  N13  1  0.418  0.582  0.134  1.0
  N  N14  1  0.918  0.082  0.366  1.0
  N  N15  1  0.082  0.918  0.634  1.0
  N  N16  1  0.530  0.970  0.750  1.0
  N  N17  1  0.970  0.530  0.250  1.0
  N  N18  1  0.470  0.030  0.250  1.0
  N  N19  1  0.030  0.470  0.750  1.0
  N  N20  1  0.842  0.158  0.954  1.0
  N  N21  1  0.158  0.842  0.046  1.0
  N  N22  1  0.658  0.342  0.454  1.0
  N  N23  1  0.342  0.658  0.546  1.0
[/CIF]
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