data_global
_chemical_name_mineral 'Tremolite'
loop_
_publ_author_name
'Warren B'
_journal_name_full 'Zeitschrift fur Kristallographie'
_journal_volume 72 
_journal_year 1929
_journal_page_first 42
_journal_page_last 57
_publ_section_title
;
 The structure of tremolite H2 Ca2 Mg5 (Si O3)8
 _cod_database_code 1011222
;
_database_code_amcsd 0018086
_chemical_formula_sum 'O24 Ca2 Mg5 Si8'
_cell_length_a 9.77
_cell_length_b 17.79999
_cell_length_c 5.26
_cell_angle_alpha 90
_cell_angle_beta 73.97
_cell_angle_gamma 90
_cell_volume 879.177
_exptl_crystal_density_diffrn      3.061
_symmetry_space_group_name_H-M 'I 1 2/m 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,1/2+z'
  'x,-y,z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,-z'
  '1/2-x,1/2+y,1/2-z'
  '-x,-y,-z'
  '1/2-x,1/2-y,1/2-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
O1   0.14000   0.08000   0.10000
O2   0.14000   0.00000  -0.40000
O3   0.14000   0.18000  -0.40000
O4   0.14000   0.25000   0.10000
O5   0.14000   0.36000  -0.25000
O6   0.14000   0.39000   0.25000
O7   0.14000   0.50000  -0.40000
Ca1   0.00000   0.28000   0.50000
Mg1   0.00000   0.09000   0.50000
Mg2   0.00000   0.17000   0.00000
Mg3   0.00000   0.00000   0.00000
Si1   0.29000   0.08000   0.01000
Si2   0.29000   0.18000  -0.49000