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#$Date: 2016-06-27 15:07:39 +0300 (Mon, 27 Jun 2016) $
#$Revision: 183977 $
#$URL: file:///home/coder/svn-repositories/cod/cif/9/00/29/9002907.cif $
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#
# This file is available in the Crystallography Open Database (COD),
# http://www.crystallography.net/. The original data for this entry
# were provided the American Mineralogist Crystal Structure Database,
# http://rruff.geo.arizona.edu/AMS/amcsd.php
#
# The file may be used within the scientific community so long as
# proper attribution is given to the journal article from which the
# data were obtained.
#
data_9002907
loop_
_publ_author_name
'Thompson, R. M.'
'Downs, R. T.'
_publ_section_title
;Model pyroxenes I: Ideal pyroxene topologies Pyroxene #1 based on HCP
 stacking sequence ABAB. Has the bonding topology of observed HT-C2/c
 pyroxenes. Note: Atoms Mg, Si, and O are assigned to atomic positions just
 for convenience.
;
_journal_name_full               'American Mineralogist'
_journal_page_first              653
_journal_page_last               666
_journal_paper_doi               10.2138/am-2003-0419
_journal_volume                  88
_journal_year                    2003
_chemical_formula_structural     Mg2(Si2O6)
_chemical_formula_sum            'Mg O3 Si'
_chemical_name_mineral           Pyroxene-ideal
_space_group_IT_number           15
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_cell_angle_alpha                90
_cell_angle_beta                 117.93835
_cell_angle_gamma                90
_cell_length_a                   7.39369100427
_cell_length_b                   6
_cell_length_c                   3.46410161514
_cell_volume                     135.765
_exptl_crystal_density_diffrn    9.823
_cod_original_formula_sum        'Mg Si O3'
_cod_database_code               9002907
_cod_struct_determination_method theoretical
loop_
_symmetry_equiv_pos_as_xyz
x,y,z
1/2+x,1/2+y,z
x,-y,1/2+z
1/2+x,1/2-y,1/2+z
-x,y,1/2-z
1/2-x,1/2+y,1/2-z
-x,-y,-z
1/2-x,1/2-y,-z
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Mg1 0.00000 0.91667 0.25000
Mg2 0.00000 0.25000 0.25000
Si 0.31250 0.08333 0.39583
O1 0.12500 0.08333 0.20833
O2 0.37500 0.25000 0.29167
O3 0.37500 0.91667 0.29167