Crystallography Open Database

Information card for entry 2002950

2002949 << 2002950 >> 2002951

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Coordinates	2002950.cif

Structure parameters

Chemical name	strontium niobium oxide
Formula	Nb5 O17 Sr5
Calculated formula	Nb5 O17 Sr5
Title of publication	Centrosymmetric or Noncentrosymmetric? Case Study and Structural Redetermination of Sr~5~Nb~5~O~17~
Authors of publication	Abrahams, Sidney C.; Schmalle, Helmut W.; Williams, Tim; Reller, Armin; Lichtenberg, Frank; Widmer, Daniel; Bednorz, J. Georg; Spreiter, Rolf; Bosshard, Christian; Günter, Peter
Journal of publication	Acta Crystallographica, Section B
Year of publication	1998
Journal volume	54
Pages of publication	399 - 416
a	32.456 ± 0.005 Å
b	5.674 ± 0.002 Å
c	3.995 ± 0.002 Å
α	90°
β	90°
γ	90°
Cell volume	735.7 ± 0.5 Å³
Cell temperature	295 ± 2 K
Ambient diffraction temperature	295 ± 2 K
Number of distinct elements	3
Space group number	58
Hermann-Mauguin space group symbol	P n n m
Hall space group symbol	-P 2 2n
Residual factor for all reflections	0.0987
Residual factor for significantly intense reflections	0.0221
Weighted residual factors for all reflections	0.0779
Weighted residual factors for significantly intense reflections	0.0551
Goodness-of-fit parameter for all reflections	0.716
Goodness-of-fit parameter for significantly intense reflections	0.809
Diffraction radiation wavelength	0.71073 Å
Diffraction radiation type	MoKα
Has coordinates	Yes
Has disorder	No
Has F_obs	No

Version history

Revision	Date	Message	Files
277834 (current)	2022-09-14	cif/ Added space group information derived from the space group operation list using the 'cif_filter' program.	2002950.cif
134621	2015-04-02	The 'cif_fix_values' script with an option '--fix-only-weighting-scheme' and 'cif_filter' script were run over CIF files which included an incorrect value of the data item '_refine_ls_weighting_scheme'. Read the log for more details. There were more than 18k CIF files with values to modify. Usually these incorrect values include comment with formulas, but values of this data item must be an enumerator. The script creates new data item '_refine_ls_weighting_details' to store these comments with formulas, and writes the enumerator 'calc' as a value of data item '_refine_ls_weighting_scheme'. There exists some exceptions in the script.	2002950.cif
26848	2011-09-28	cif/2/, hkl/2/, html/ Reorganising CIFs of the range 2* into the "prefix-directory" tree.	2002950.cif
5310	2011-01-02	cif/ Running cif_fix_enum with the core CIF dictionary on COD ranges 2, 8 and 9. Range 9 remained unchanged, and in ranges 2 and 8 there were 17309 modified files, most changes were fixes enumerator case.	2002950.cif
966	2010-01-30	cif/ Adding _cod_database_code tags to all COD entries. Adding tag description to the cif_cod.dic dictionary so that COD entries can be validated.	2002950.cif
846	2009-11-14	cif/ Fixing _journal_volume values that had series letters prepended to them. Now the series letters are appended to the _journal_name_full, if needed, and the _journal_volume is purely numeric. To mimimise textual changes to CIFs this was done in several stages. First of all, a list of _journal_volume was compiled from the COD CIF collection: bash -xc 'find ? -name \*.cif \ \| xargs cif_values \ --file \ --tag _journal_volume' \ >& cod-journal-volumes-`-date`.log & giving us a cod-journal-volumes-2009.11.13.log file (committed for reference as well). Then a list of volume names with letters was extracted and most of them transformed automatically into a correct form: awk '$3~/^[A-Z][0-9]/' cod-journal-volumes-2009.11.13.log \ \| awk '{print $1}' \ \| xargs -n1 -iI \ bash -c 'echo === I ===;\ awk "/^#/,/^data_/{print}/^data_/{exit}" I > tmp-$$; \ cif_adjust_journal_name_volume I \ \| grep -E "_journal_name_full\|_journal_volume" >> tmp-$$; \ awk "/^data_/,/\$eof/" I \ \| grep -vE "^(data_\|_journal_name_full\|_journal_volume)" >> tmp-$$;\ mv -v tmp-$$ I' Note that this procedure assumes that all tags are at the beginning of the line, each value follows its tag on the same line, and there is only one tag per line. This procedure is not suitable for general CIFs, but fortunately, only very few CIFs in COD do not conform these rules. After the automatic conversion, a syntax check was run: svn st ? \ \| awk '{print $NF}' \ \| xargs -n1 -iI sh -c 'echo -n I"\r"; vcif -l 2048 I \|\| echo "!!! I !!!\n"' Entries that were found to have errors (very few, less than 10) were reverted and fixed manually. The entries that had letters embedded into them were grepped separately: awk '$3~/[A-Z][0-9]/' cod-journal-volumes-2009.11.13.log \ \| awk '$3~/^[^A-Z]/' and fixed manually. After all fixes, the previous 'vcif' test was rerun, yielding no syntax errors, and in addition a 'cif_filter' roundtrip test was run: svn st ? \ \| awk '{print $NF}' \ \| xargs -n1 -iI \ bash -c ' \ echo -en I "\r"; \ diff \ <(cif_filter I >& /dev/null) \ <(cif_filter I \| cif_filter >& /dev/null) \ \|\| echo "!!! I !!!\n"' This last test discovered one misspelled '_journal_yrae' tag in the 2/2003193.cif entry that was fixed by hand.	2002950.cif
19	2008-01-26	Changing all end-of-line codes from DOS style to UNIX style in all COD CIF files, for more convenient processing: In the cod/cif/ directory: ff \*.cif \| xargs perl -i -pe 's/\r\n/\n/'	2002950.cif
14	2008-01-14	Appending a header with SVN keywords, COD URL and copying policy to all COD CIF files.	2002950.cif
13	2008-01-13	Setting the svn:keywords property to "Author Date Revision URL Id" for all CIF files in the cod/cif directory.	2002950.cif
1	2007-11-30	Adding all .cif files from the COD, downloaded in a Cod.zip file on 2007.02.07 (and the same Cod.zip is downloadable today, on 2007.11.29)	2002950.cif