Dear yashwanth padarthi I do not have the powder diffraction file at hand at the moment. In a CIF file for your structural compounds all atoms are listed that are in the asymmetric unit of the structure. The symmetry operations of the space group will expand these to the full content. Take the following cif File for Bi2O2:
1 #------------------------------------------------------------------------------ 2 #$Date: 2015-07-12 19:53:27 +0300 (Sun, 12 Jul 2015) $ 3 #$Revision: 147647 $ 4 #$URL: svn://www.crystallography.net/cod/cif/1/52/64/1526458.cif $ 5 #------------------------------------------------------------------------------ 6 # 7 # This file is available in the Crystallography Open Database (COD), 8 # http://www.crystallography.net/ 9 # 10 # All data on this site have been placed in the public domain by the 11 # contributors. 12 # 13 data_1526458 14 loop_ 15 _publ_author_name 16 'Ivanov, S.A.' 17 'Orlov, V.G.' 18 'Tellgren, R.' 19 'Rundlof, H.' 20 _publ_section_title 21 ; 22 Structural studies of alpha-(Bi2 O3) by neutron powder diffraction 23 ; 24 _journal_name_full 'Powder Diffraction' 25 _journal_page_first 227 26 _journal_page_last 230 27 _journal_volume 16 28 _journal_year 2001 29 _chemical_formula_sum 'Bi2 O3' 30 _chemical_name_systematic 'Bi2 O3' 31 _space_group_IT_number 14 32 _symmetry_space_group_name_Hall '-P 2ybc' 33 _symmetry_space_group_name_H-M 'P 1 21/c 1' 34 _cell_angle_alpha 90 35 _cell_angle_beta 112.97 36 _cell_angle_gamma 90 37 _cell_formula_units_Z 4 38 _cell_length_a 5.8444 39 _cell_length_b 8.1574 40 _cell_length_c 7.5032 41 _cell_volume 329.352 42 _citation_journal_id_ASTM PODIE2 43 _cod_data_source_file Ivanov_PODIE2_2001_1874.cif 44 _cod_data_source_block Bi2O3 45 _cod_original_cell_volume 329.3523 46 _cod_database_code 1526458 47 loop_ 48 _symmetry_equiv_pos_as_xyz 49 x,y,z 50 -x,y+1/2,-z+1/2 51 -x,-y,-z 52 x,-y-1/2,z-1/2 53 loop_ 54 _atom_site_label 55 _atom_site_type_symbol 56 _atom_site_fract_x 57 _atom_site_fract_y 58 _atom_site_fract_z 59 _atom_site_occupancy 60 _atom_site_U_iso_or_equiv 61 O1 O-2 0.7771 0.3043 0.7074 1 0.0 62 Bi1 Bi+3 0.5227 0.1837 0.3615 1 0.0 63 O3 O-2 0.268 0.0283 0.5106 1 0.0 64 Bi2 Bi+3 0.0401 0.0426 0.7762 1 0.0 65 O2 O-2 0.2351 0.0477 0.1272 1 0.0 Lines 61 to 65 contain an entry for all atoms, two Bi and 2 O. In this particular compound, all atoms are on so called general positions. This means that no symmetry element copies the atoms onto itself. Now take another Bi2O3 Phase: 1 #------------------------------------------------------------------------------ 2 #$Date: 2015-01-27 21:58:39 +0200 (Tue, 27 Jan 2015) $ 3 #$Revision: 130149 $ 4 #$URL: svn://www.crystallography.net/cod/cif/1/01/03/1010313.cif $ 5 #------------------------------------------------------------------------------ 6 # 7 # This file is available in the Crystallography Open Database (COD), 8 # http://www.crystallography.net/ 9 # 10 # All data on this site have been placed in the public domain by the 11 # contributors. 12 # 13 data_1010313 14 loop_ 15 _publ_author_name 16 'Sillen, L G' 17 _publ_section_title 'X-Ray Studies on Bismuth Trioxide' 18 _journal_coden_ASTM ARKGAJ 19 _journal_issue 18 20 _journal_name_full 'Arkiv foer Kemi, Mineralogi och Geologi, A' 21 _journal_page_first 1 22 _journal_page_last 15 23 _journal_volume 12 24 _journal_year 1938 25 _chemical_formula_structural 'Bi2 O3' 26 _chemical_formula_sum 'Bi2 O3' 27 _chemical_name_systematic 'Bismuth oxide' 28 _space_group_IT_number 197 29 _symmetry_cell_setting cubic 30 _symmetry_Int_Tables_number 197 31 _symmetry_space_group_name_Hall 'I 2 2 3' 32 _symmetry_space_group_name_H-M 'I 2 3' 33 _cell_angle_alpha 90 34 _cell_angle_beta 90 35 _cell_angle_gamma 90 > Dear sir, 36 _cell_formula_units_Z 12 37 _cell_length_a 10.08 38 _cell_length_b 10.08 39 _cell_length_c 10.08 40 _cell_volume 1024.2 41 _cod_database_code 1010313 42 loop_ 43 _symmetry_equiv_pos_as_xyz 44 x,y,z 45 y,z,x 46 z,x,y 47 x,-y,-z 48 y,-z,-x 49 z,-x,-y 50 -x,y,-z 51 -y,z,-x 52 -z,x,-y 53 -x,-y,z 54 -y,-z,x 55 -z,-x,y 56 1/2+x,1/2+y,1/2+z 57 1/2+y,1/2+z,1/2+x 58 1/2+z,1/2+x,1/2+y 59 1/2+x,1/2-y,1/2-z 60 1/2+y,1/2-z,1/2-x 61 1/2+z,1/2-x,1/2-y 62 1/2-x,1/2+y,1/2-z 63 1/2-y,1/2+z,1/2-x 64 1/2-z,1/2+x,1/2-y 65 1/2-x,1/2-y,1/2+z 66 1/2-y,1/2-z,1/2+x 67 1/2-z,1/2-x,1/2+y 68 loop_69 _atom_site_label 70 _atom_site_type_symbol 71 _atom_site_symmetry_multiplicity 72 _atom_site_Wyckoff_symbol 73 _atom_site_fract_x 74 _atom_site_fract_y 75 _atom_site_fract_z 76 _atom_site_occupancy 77 _atom_site_attached_hydrogens 78 _atom_site_calc_flag 79 Bi1 Bi3+ 24 f 0.32 0.18 0.02 1. 0 d 80 O1 O2- 24 f 0.36 0.08 0.21 1. 0 d 81 O2 O2- 12 d 0.19 0. 0. 1. 0 d 82 loop_ 83 _atom_type_symbol 84 _atom_type_oxidation_number 85 Bi3+ 3.000 86 O2- -2.000 In this case only one line is there for Bi and two for O. The first two atom types are on a general position, while the second O is on a special positions and some of the space group symmetry elements copy these atoms onto themselves. Thus the number of atoms listed will depend on the actual structure at hand. Reinhard Neder > > In the Data Sheet Provided in any refined crystallographic data in the > atomic coordinates section we are given with elements for example in Bi2 > O3(96-101-0312) only for Bi & O all coordinates are present but if i take > BICOVOX(96-151-6578)we have Bi,Co,V,Bi,O,O,O,O,O how to interpret them > according to the formula of compound > Do they mean that only these elements constitute in every unit cell of the > compound in which they are present?how do they change with compound to > compound? > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > -- Prof. Dr. Reinhard Neder Kristallographie und Strukturphysik Universität Erlangen Staudtststr. 3; 91058 Erlangen tel. +49-9131-8525191 fax +49-9131-8525182 -- DISCUS Workshop 2016 http://www.lks.physik.uni-erlangen.de/DISCUS/index.html
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
