data_global
_chemical_name_mineral 'Ice IV'
loop_
_publ_author_name
'Engelhardt H'
'Kamb B'
_journal_name_full 'Journal of Chemical Physics'
_journal_volume 75 
_journal_year 1981
_journal_page_first 5887
_journal_page_last 5899
_publ_section_title
;
 Structure of ice IV, a metastable high-pressure phase
 Note: T = 110 K, synthesized at 4-5.5 kb
;
_database_code_amcsd 0018368
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'O H2'
_cell_length_a 7.60
_cell_length_b 7.60
_cell_length_c 7.60
_cell_angle_alpha 70.1
_cell_angle_beta 70.1
_cell_angle_gamma 70.1
_cell_volume 375.394
_exptl_crystal_density_diffrn      1.275
_symmetry_space_group_name_H-M 'R -3 c'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2-x,1/2-z,1/2-y'
  '-z,-x,-y'
  '1/2+y,1/2+x,1/2+z'
  'y,z,x'
  '1/2-z,1/2-y,1/2-x'
  '-x,-y,-z'
  '1/2+x,1/2+z,1/2+y'
  'z,x,y'
  '1/2-y,1/2-x,1/2-z'
  '-y,-z,-x'
  '1/2+z,1/2+y,1/2+x'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_U_iso_or_equiv
O1   0.38040  -0.11090  -0.23960   1.00000 ?
O2   0.08550   0.08550   0.08550   1.00000 ?
H1   0.03000   0.03000   0.03000   0.50000   0.02406
H2   0.14000   0.18000   0.01000   0.50000   0.02406
H3   0.21000   0.33000  -0.10000   0.50000   0.02406
H4   0.30000  -0.01000  -0.28000   0.50000   0.02406
H5   0.22000   0.11000  -0.34000   0.50000   0.02406
H6   0.28000   0.41000  -0.02000   0.50000   0.02406
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
O1 0.02493 0.01767 0.02275 -0.00508 -0.00944 -0.02227
O2 0.01815 0.01815 0.01815 -0.01017 -0.01017 -0.01017