data_Enstatite

_chemical_name_systematic          'Dimagnesium catena-disilicate'
_chemical_name_mineral             'Enstatite'
_chemical_formula_structural       'Mg2 (Si2 O6)'
_chemical_formula_sum              'Mg2 O6 Si2'

_publ_section_title                
;
High temperature single crystal X-ray diffraction studies of the ortho-
proto phase transition in enstatite, Mg2 Si2 O6 at 1360 K
;
loop_
_publ_author_name                  
  'Yang, H X'
  'Ghose, S'
_journal_name_full                 'Physics and Chemistry of Minerals (Germany)'
_journal_coden_ASTM                PCMIDU
_journal_volume                    22
_journal_year                      1995
_journal_page_first                300
_journal_page_last                 310

_cell_length_a                     18.25099(400)
_cell_length_b                     8.814(1)
_cell_length_c                     5.181(1)
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  90
_cell_volume                       833.4
_cell_formula_units_Z              8

_symmetry_space_group_name_H-M     'P b c a'
_symmetry_Int_Tables_number        61
_symmetry_cell_setting             orthorhombic

loop_
_symmetry_equiv_pos_as_xyz         
  'x,y,z'
  '1/2+x,1/2-y,-z'
  '-x,1/2+y,1/2-z'
  '1/2-x,-y,1/2+z'
  '-x,-y,-z'
  '1/2-x,1/2+y,z'
  'x,1/2-y,1/2+z'
  '1/2+x,y,1/2-z'

loop_
_atom_type_symbol
_atom_type_oxidation_number
  Mg2+   2.000
  Si4+   4.000
  O2-   -2.000

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_calc_flag
  Mg1   Mg2+   8 c 0.3758(1) 0.6537(1) 0.8660(1) 1.  0 d
  Mg2   Mg2+   8 c 0.3768(1) 0.4869(1) 0.3590(1) 1.  0 d
  Si1   Si4+   8 c 0.2717(1) 0.3415(1) 0.0505(1) 1.  0 d
  Si2   Si4+   8 c 0.4735(1) 0.3374(1) 0.7983(1) 1.  0 d
  O1    O2-    8 c 0.1834(1) 0.3400(1) 0.0356(2) 1.  0 d
  O2    O2-    8 c 0.5625(1) 0.3403(1) 0.8002(2) 1.  0 d
  O3    O2-    8 c 0.3108(1) 0.5027(1) 0.0432(2) 1.  0 d
  O4    O2-    8 c 0.4327(1) 0.4833(1) 0.6896(2) 1.  0 d
  O5    O2-    8 c 0.3032(1) 0.2226(1) 0.8321(2) 1.  0 d
  O6    O2-    8 c 0.4475(1) 0.1955(1) 0.6040(2) 1.  0 d

_refine_ls_R_factor_all            0.027