#------------------------------------------------------------------------------
#$Date: 2012-02-28 17:44:07 +0200 (Tue, 28 Feb 2012) $
#$Revision: 35913 $
#$URL: file:///home/coder/svn-repositories/cod/cif/9/01/36/9013636.cif $
#------------------------------------------------------------------------------
#
# 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_9013636
loop_
_publ_author_name
'Merlini, M.'
'Gemmi, M.'
'Hanfland, M.'
'Crichton, W.'
_publ_section_title
;
 High-pressure behavior of akermanite and gehlenite and phase stability
 of the normal structures in melelites
 Note: P = 5 GPa
 Locality: synthetic
;
_journal_name_full               'American Mineralogist'
_journal_page_first              704
_journal_page_last               709
_journal_volume                  94
_journal_year                    2009
_chemical_formula_sum            'Ca2 Mg O7 Si2'
_chemical_name_mineral           Akermanite
_space_group_IT_number           113
_symmetry_space_group_name_Hall  'P -4 2ab'
_symmetry_space_group_name_H-M   'P -4 21 m'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_length_a                   7.740
_cell_length_b                   7.740
_cell_length_c                   4.932
_cell_volume                     295.464
_diffrn_ambient_pressure         5e+06
_exptl_crystal_density_diffrn    3.064
_[local]_cod_chemical_formula_sum_orig 'Mg Ca2 Si2 O7'
_cod_database_code               9013636
_amcsd_database_code             AMCSD#0004932
loop_
_symmetry_equiv_pos_as_xyz
x,y,z
1/2-y,1/2-x,z
y,-x,-z
1/2-x,1/2+y,-z
-x,-y,z
1/2+y,1/2+x,z
-y,x,-z
1/2+x,1/2-y,-z
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Mg 0.00000 0.00000 0.00000
Ca 0.33430 0.16570 0.50650
Si 0.14160 0.35840 0.93700
O1 0.00000 0.50000 -0.19500
O2 0.14380 0.35620 0.26000
O3 0.08030 0.18430 0.78200