data_9001564
_chemical_name 'Poldervaartite'
loop_
_publ_author_name
'Dai Y S'
'Harlow G E'
'McGhie A R'
_journal_name_full "American Mineralogist"
_journal_volume 78
_journal_year 1993
_journal_page_first 1082
_journal_page_last 1087
_publ_section_title
;
 Poldervaartite, Ca(Ca0.5Mn0.5)(SiO3OH)(OH), a new acid nesosilicate from the
 Kalahari manganese field, South Africa: Crystal structure and description
;
_chemical_formula_sum 'Ca1.67 Mn.33 Si O5 H2'
_cell_length_a 9.398
_cell_length_b 9.139
_cell_length_c 10.535
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 904.833
_symmetry_space_group_name_H-M 'P b c a'
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  'x,1/2-y,1/2+z'
  '-x,1/2+y,1/2-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-y,-z'
  '1/2+x,y,1/2-z'
  '1/2-x,-y,1/2+z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_Uiso_or_equiv
Ca1   0.15406   0.49326   0.39021   1.00000 ?
Ca2   0.51266   0.33390   0.43048   0.67000 ?
Mn   0.51266   0.33390   0.43048   0.33000 ?
Si   0.32973   0.21515   0.65939   1.00000 ?
O-h1   0.25180   0.35020   0.57350   1.00000 ?
O2  -0.05590   0.35900   0.43680   1.00000 ?
O3   0.10200   0.71010   0.28290   1.00000 ?
O-h4   0.39650   0.54920   0.39800   1.00000 ?
O5   0.20190   0.39860   0.18930   1.00000 ?
H1   0.25700   0.07400   0.11700   1.00000   0.03000
H2  -0.08400   0.58800   0.17300   1.00000   0.03000