data_Beryl
_chemical_name_systematic
;
Dialuminium Triberyllium Hexasilicate
;
_chemical_formula_structural       'Al2 Be3 Si6 O18'
_chemical_formula_sum              'Al2 Be3 O18 Si6'
_chemical_name_mineral             Beryl
_cell_length_a                     9.209(6)
_cell_length_b                     9.209(6)
_cell_length_c                     9.197(6)
_cell_angle_alpha                  90.
_cell_angle_beta                   90.
_cell_angle_gamma                  120.
_cell_volume                       675.46
_cell_formula_units_Z              2
_symmetry_space_group_name_H-M     'P 6/m c c'
_symmetry_Int_Tables_number        192
loop_
_symmetry_equiv_pos_site_id
_symmetry_equiv_pos_as_xyz
  1	'x, x-y, z+1/2'
  2	'-x+y, y, z+1/2'
  3	'-y, -x, z+1/2'
  4	'x, x-y, -z+1/2'
  5	'-x+y, y, -z+1/2'
  6	'-y, -x, -z+1/2'
  7	'x-y, x, z'
  8	'y, -x+y, z'
  9	'-x, -y, z'
 10	'x-y, x, -z'
 11	'y, -x+y, -z'
 12	'-x, -y, -z'
 13	'-x, -x+y, -z+1/2'
 14	'x-y, -y, -z+1/2'
 15	'y, x, -z+1/2'
 16	'-x, -x+y, z+1/2'
 17	'x-y, -y, z+1/2'
 18	'y, x, z+1/2'
 19	'-x+y, -x, -z'
 20	'-y, x-y, -z'
 21	'x, y, -z'
 22	'-x+y, -x, z'
 23	'-y, x-y, z'
 24	'x, y, z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
Al3+	3
Be2+	2
O2-	-2
Si4+	4
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_attached_hydrogens
_atom_site_B_iso_or_equiv
Al1 Al3+ 4 c 0.3333 0.6667 0.25 1. 0 0.55 
Be1 Be2+ 6 f 0.5 0 0.25 1. 0 0.67 
Si1 Si4+ 12 l 0.3784(4) 0.1156(4) 0 1. 0 0.65 
O1 O2- 12 l 0.3092(11) 0.2357(12) 0 1. 0 1.34 
O2 O2- 24 m 0.4981(7) 0.1447(7) 0.1445(5) 1. 0 0.71 


