The material described by U4SiN3 is Caswellsilverite-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to two equivalent Si(1), two equivalent N(1), and two equivalent N(2) atoms to form USi2N4 octahedra that share corners with six equivalent U(1)Si2N4 octahedra, edges with four equivalent U(1)Si2N4 octahedra, and edges with eight equivalent U(2)SiN5 octahedra. The corner-sharing octahedra are not tilted. In the second U site, U(2) is bonded to one Si(1), one N(2), and four equivalent N(1) atoms to form distorted USiN5 octahedra that share corners with six equivalent U(2)SiN5 octahedra, edges with four equivalent U(2)SiN5 octahedra, and edges with eight equivalent U(1)Si2N4 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. Si(1) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form SiU6 octahedra that share corners with two equivalent N(2)U6 octahedra, corners with four equivalent Si(1)U6 octahedra, edges with four equivalent N(2)U6 octahedra, and edges with eight equivalent N(1)U6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent N sites. In the first N site, N(1) is bonded to two equivalent U(1) and four equivalent U(2) atoms to form NU6 octahedra that share corners with six equivalent N(1)U6 octahedra, edges with four equivalent Si(1)U6 octahedra, edges with four equivalent N(1)U6 octahedra, and edges with four equivalent N(2)U6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second N site, N(2) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form NU6 octahedra that share corners with two equivalent Si(1)U6 octahedra, corners with four equivalent N(2)U6 octahedra, edges with four equivalent Si(1)U6 octahedra, and edges with eight equivalent N(1)U6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_U4SiN3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.148
_cell_length_b   6.148
_cell_length_c   6.148
_cell_angle_alpha   130.740
_cell_angle_beta   130.740
_cell_angle_gamma   72.227
_symmetry_Int_Tables_number   1
_cell_volume   130.443
_cell_formula_units_Z   1
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
  U  U0  1  0.000  0.500  0.500  1.0
  U  U1  1  0.231  0.231  0.000  1.0
  U  U2  1  0.500  0.000  0.500  1.0
  U  U3  1  0.769  0.769  0.000  1.0
  Si  Si4  1  0.500  0.500  0.000  1.0
  N  N5  1  0.750  0.250  0.500  1.0
  N  N6  1  0.000  0.000  0.000  1.0
  N  N7  1  0.250  0.750  0.500  1.0
[/CIF]
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The material described by U4SiN3 is Caswellsilverite-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to two equivalent Si(1), two equivalent N(1), and two equivalent N(2) atoms to form USi2N4 octahedra that share corners with six equivalent U(1)Si2N4 octahedra, edges with four equivalent U(1)Si2N4 octahedra, and edges with eight equivalent U(2)SiN5 octahedra. The corner-sharing octahedra are not tilted. In the second U site, U(2) is bonded to one Si(1), one N(2), and four equivalent N(1) atoms to form distorted USiN5 octahedra that share corners with six equivalent U(2)SiN5 octahedra, edges with four equivalent U(2)SiN5 octahedra, and edges with eight equivalent U(1)Si2N4 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. Si(1) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form SiU6 octahedra that share corners with two equivalent N(2)U6 octahedra, corners with four equivalent Si(1)U6 octahedra, edges with four equivalent N(2)U6 octahedra, and edges with eight equivalent N(1)U6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent N sites. In the first N site, N(1) is bonded to two equivalent U(1) and four equivalent U(2) atoms to form NU6 octahedra that share corners with six equivalent N(1)U6 octahedra, edges with four equivalent Si(1)U6 octahedra, edges with four equivalent N(1)U6 octahedra, and edges with four equivalent N(2)U6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the second N site, N(2) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form NU6 octahedra that share corners with two equivalent Si(1)U6 octahedra, corners with four equivalent N(2)U6 octahedra, edges with four equivalent Si(1)U6 octahedra, and edges with eight equivalent N(1)U6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_U4SiN3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.148
_cell_length_b   6.148
_cell_length_c   6.148
_cell_angle_alpha   130.740
_cell_angle_beta   130.740
_cell_angle_gamma   72.227
_symmetry_Int_Tables_number   1
_cell_volume   130.443
_cell_formula_units_Z   1
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
  U  U0  1  0.000  0.500  0.500  1.0
  U  U1  1  0.231  0.231  0.000  1.0
  U  U2  1  0.500  0.000  0.500  1.0
  U  U3  1  0.769  0.769  0.000  1.0
  Si  Si4  1  0.500  0.500  0.000  1.0
  N  N5  1  0.750  0.250  0.500  1.0
  N  N6  1  0.000  0.000  0.000  1.0
  N  N7  1  0.250  0.750  0.500  1.0
[/CIF]
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