data_72938-ICSD
#©2011 by Fachinformationszentrum Karlsruhe, and the U.S. Secretary of 
#Commerce on behalf of the United States.  All rights reserved.
_database_code_ICSD                72938
_audit_creation_date               1994/06/30
_audit_update_record               2007/08/01
_chemical_name_systematic          'Dialuminium Silicate Dihydroxide'
_chemical_formula_structural       'Al2 (Si O4) (O H)2'
_chemical_formula_sum              'H2 Al2 O6 Si1'
_chemical_name_mineral             Topaz
_publ_section_title
;
Synthesis, stability and properties of Al2 Si O4 (O H)2: a fully 
hydrated analogue of topaz
;
loop_
_citation_id
_citation_journal_abbrev
_citation_year
_citation_journal_volume
_citation_page_first
_citation_page_last
_citation_journal_id_ASTM
primary 'American Mineralogist' 1993 78 285 297 AMMIAY
_publ_author_name
;
Wunder, B.;Rubie, D.C.;Ross, C.R.;Medenbach, O.;Seifert, F.;Schreyer, 
W.
;
_cell_length_a                     4.7238(30)
_cell_length_b                     8.9473(69)
_cell_length_c                     8.3900(77)
_cell_angle_alpha                  90.
_cell_angle_beta                   90.
_cell_angle_gamma                  90.
_cell_volume                       354.61
_cell_formula_units_Z              4
_symmetry_space_group_name_H-M     'P b n m'
_symmetry_Int_Tables_number        62
_refine_ls_R_factor_all            0.046
loop_
_symmetry_equiv_pos_site_id
_symmetry_equiv_pos_as_xyz
  1	'-x+1/2, y+1/2, z'
  2	'x, y, -z+1/2'
  3	'x+1/2, -y+1/2, z+1/2'
  4	'-x, -y, -z'
  5	'x+1/2, -y+1/2, -z'
  6	'-x, -y, z+1/2'
  7	'-x+1/2, y+1/2, -z+1/2'
  8	'x, y, z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
Al3+	3
H1+	1
O2-	-2
Si4+	4
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
Al1 Al3+ 8 d -.0948(2) 0.1322(1) 0.0798(1) 1. 0 
Si1 Si4+ 4 c 0.4019(2) -.0595(1) 0.25 1. 0 
O1 O2- 4 c 0.7103(5) 0.0261(2) 0.25 1. 0 
O2 O2- 4 c 0.0554(5) 0.2558(2) 0.25 1. 0 
O3 O2- 8 d 0.2142(3) -.0069(2) 0.0940(2) 1. 0 
O4 O2- 8 d 0.5897(4) 0.2508 0.0665(2) 1. 1 
#Position of 8 Elements of H Are Undetermined.
loop_
_atom_site_aniso_label
_atom_site_aniso_type_symbol
_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
Al1 Al3+ 0.0098(3) 0.0089(3) 0.0137(3) 0.0002(2) 0.0002(2) 0.0000(2)
Si1 Si4+ 0.0090(3) 0.0088(4) 0.0145(4) 0.0000(3) 0 0
O1 O2- 0.0088(8) 0.0095(9) 0.0150(9) -.0006(8) 0 0
O2 O2- 0.0108(10) 0.0102(9) 0.0150(9) -.0003(7) 0 0
O3 O2- 0.0101(6) 0.0100(6) 0.0136(6) 0.0010(5) 0.0006(5) 0.0000(5)
O4 O2- 0.0106(6) 0.0122(7) 0.0167(6) 0.0021(6) 0.0001(6) 0.0016(5)
#End of data_72938-ICSD


