data_9000274
_publ_section_title
;
 Computer-simulated crystal structures of observed and hypothetical Mg2SiO4
 polymorphs of low and high density
 Sr2PbO4 structure
;
_journal_name_full               'American Mineralogist'
_journal_page_first              709
_journal_page_last               731
_journal_volume                  57
_journal_year                    1972
_chemical_formula_structural     'Mg2 (Si O4)'
_chemical_formula_sum            'Mg2 O4 Si'
_space_group_IT_number           55
_symmetry_space_group_name_Hall  '-P 2 2ab'
_symmetry_space_group_name_H-M   'P b a m'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_length_a                   4.98
_cell_length_b                   8.85
_cell_length_c                   2.75
_cell_volume                     121.201
_exptl_crystal_density_diffrn    3.855
_[local]_cod_chemical_formula_sum_orig 'Si Mg2 O4'
_cod_database_code               9000274
loop_
_symmetry_equiv_pos_as_xyz
x,y,z
1/2+x,1/2-y,z
1/2-x,1/2+y,-z
1/2-x,1/2+y,z
1/2+x,1/2-y,-z
x,y,-z
-x,-y,z
-x,-y,-z
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Si 0.00000 0.00000 0.00000
Mg 0.08190 0.33290 0.50000
O1 0.21640 0.04480 0.50000
O2 0.39250 0.30870 0.00000
