The material described by BC7 is beta beryllia-like structured and crystallizes in the tetragonal P-4m2 space group. B(1) is bonded to four equivalent C(3) atoms to form BC4 tetrahedra that share corners with four equivalent B(1)C4 tetrahedra and corners with eight equivalent C(4)C4 tetrahedra. There are four inequivalent C sites. In the first C site, C(1) is bonded to four equivalent C(2) atoms to form corner-sharing CC4 tetrahedra. In the second C site, C(2) is bonded to two equivalent C(1) and two equivalent C(4) atoms to form CC4 tetrahedra that share corners with four equivalent C(3)B2C2 tetrahedra and corners with eight equivalent C(2)C4 tetrahedra. In the third C site, C(3) is bonded to two equivalent B(1) and two equivalent C(4) atoms to form CB2C2 tetrahedra that share corners with four equivalent C(2)C4 tetrahedra and corners with eight equivalent C(3)B2C2 tetrahedra. In the fourth C site, C(4) is bonded to two equivalent C(2) and two equivalent C(3) atoms to form CC4 tetrahedra that share corners with four equivalent B(1)C4 tetrahedra, corners with four equivalent C(1)C4 tetrahedra, and corners with four equivalent C(4)C4 tetrahedra. is represented by the CIF card [CIF]
data_BC7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.518
_cell_length_b   2.518
_cell_length_c   7.494
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   47.530
_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
  B  B0  1  0.000  0.000  0.500  1.0
  C  C1  1  0.000  0.000  0.000  1.0
  C  C2  1  0.000  0.500  0.119  1.0
  C  C3  1  0.500  0.000  0.881  1.0
  C  C4  1  0.000  0.500  0.642  1.0
  C  C5  1  0.500  0.000  0.358  1.0
  C  C6  1  0.500  0.500  0.242  1.0
  C  C7  1  0.500  0.500  0.758  1.0
[/CIF]
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The material described by BC7 is beta beryllia-like structured and crystallizes in the tetragonal P-4m2 space group. B(1) is bonded to four equivalent C(3) atoms to form BC4 tetrahedra that share corners with four equivalent B(1)C4 tetrahedra and corners with eight equivalent C(4)C4 tetrahedra. There are four inequivalent C sites. In the first C site, C(1) is bonded to four equivalent C(2) atoms to form corner-sharing CC4 tetrahedra. In the second C site, C(2) is bonded to two equivalent C(1) and two equivalent C(4) atoms to form CC4 tetrahedra that share corners with four equivalent C(3)B2C2 tetrahedra and corners with eight equivalent C(2)C4 tetrahedra. In the third C site, C(3) is bonded to two equivalent B(1) and two equivalent C(4) atoms to form CB2C2 tetrahedra that share corners with four equivalent C(2)C4 tetrahedra and corners with eight equivalent C(3)B2C2 tetrahedra. In the fourth C site, C(4) is bonded to two equivalent C(2) and two equivalent C(3) atoms to form CC4 tetrahedra that share corners with four equivalent B(1)C4 tetrahedra, corners with four equivalent C(1)C4 tetrahedra, and corners with four equivalent C(4)C4 tetrahedra. is represented by the CIF card [CIF]
data_BC7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.518
_cell_length_b   2.518
_cell_length_c   7.494
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   47.530
_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
  B  B0  1  0.000  0.000  0.500  1.0
  C  C1  1  0.000  0.000  0.000  1.0
  C  C2  1  0.000  0.500  0.119  1.0
  C  C3  1  0.500  0.000  0.881  1.0
  C  C4  1  0.000  0.500  0.642  1.0
  C  C5  1  0.500  0.000  0.358  1.0
  C  C6  1  0.500  0.500  0.242  1.0
  C  C7  1  0.500  0.500  0.758  1.0
[/CIF]
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