#------------------------------------------------------------------------------
#$Date: 2008-01-14 00:15:36 +0200 (Mon, 14 Jan 2008) $
#$Revision: 14 $
#$URL: file:///home/coder/svn-repositories/cod/cif/5/5000232.cif $
#------------------------------------------------------------------------------
#
# This file is available in the Crystallography Open Database (COD),
# http://www.crystallography.net/
#
# All data on this site have been placed in the public domain by the
# contributors.
#
data_5000232
_chemical_name_systematic          'Dicalcium zinc disilicate'
_chemical_name_mineral             'Hardystonite'
_chemical_formula_sum              'Ca2 O7 Si2 Zn'
_publ_section_title
;
Refinemente of the crystal structure of Hardystonite, Ca2 Zn Si2 O7
;
_publ_author_name                  'Louisnathan, S J'
_journal_name_full
;
Zeitschrift fuer Kristallographie, Kristallgeometrie, Kristallphysik,
Kristallchemie (-144,1977)
;
_journal_volume                    130
_journal_year                      1969
_journal_page_first                427
_journal_page_last                 437
_cell_length_a                     7.8279(10)
_cell_length_b                     7.8279(10)
_cell_length_c                     5.0138(6)
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  90
_cell_volume                       307.2
_cell_formula_units_Z              2
_exptl_crystal_density_meas        3.4
_symmetry_space_group_name_H-M     'P -4 21 m'
_symmetry_Int_Tables_number        113
_symmetry_cell_setting             tetragonal
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '1/2-x,1/2+y,-z'
  '-x,-y,z'
  '1/2+x,1/2-y,-z'
  '-y,x,-z'
  '1/2+y,1/2+x,z'
  'y,-x,-z'
  '1/2-y,1/2-x,z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Ca2+   2.000
  Zn2+   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
  Ca1   Ca2+   4 e 0.3322(1) 0.1678(1) 0.5061(3) 1.  0 d
  Zn1   Zn2+   2 a 0. 0. 0. 1.  0 d
  Si1   Si4+   4 e 0.1393(2) 0.3607(2) 0.9304(3) 1.  0 d
  O1    O2-    2 c 0.5 0. 0.1771(15) 1.  0 d
  O2    O2-    4 e 0.1400(5) 0.3600(5) 0.2551(11) 1.  0 d
  O3    O2-    8 f 0.0818(7) 0.1885(5) 0.7847(9) 1.  0 d
_refine_ls_R_factor_all            0.053