Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background

A new structural model is proposed for cubic nitroprussides and the crystal structure for the complex salts of Fe 2+ , Co 2+ , and Ni 2+ refined in that model. In cubic nitroprussides the building unit, Fe CN 5NO 2−, and the assembling metal M=Fe2+,Co2+,Ni2+ , have 3 4 occupancy with three formula u...

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Detalles Bibliográficos
Autores: GOMEZ, A., RODRIGUEZ HERNANDEZ, J., REGUERA, E.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2007
País:México
Institución:Instituto Politécnico Nacional
Repositorio:Repositorio Digital del IPN
OAI Identifier:oai:www.repositoriodigital.ipn.mx:123456789/11202
Acceso en línea:http://hdl.handle.net/123456789/713
http://www.repositoriodigital.ipn.mx/handle/123456789/11202
Access Level:acceso abierto
Palabra clave:nitroprusside
crystal structure
porous material
Rietveld refinement,
Prussian blue analogues
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spelling Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the backgroundGOMEZ, A.RODRIGUEZ HERNANDEZ, J.REGUERA, E.nitroprussidecrystal structureporous materialRietveld refinement,Prussian blue analoguesA new structural model is proposed for cubic nitroprussides and the crystal structure for the complex salts of Fe 2+ , Co 2+ , and Ni 2+ refined in that model. In cubic nitroprussides the building unit, Fe CN 5NO 2−, and the assembling metal M=Fe2+,Co2+,Ni2+ , have 3 4 occupancy with three formula units per cell Z=3 . This leads to certain structural disorder and to different local environments for the outer metal. The crystallographic results are supported by the Mössbauer and infrared data. The XRD powder patterns, index in a cubic cell Fm3m space group , show a sinuous background because of diffuse scattering from positional disorder of the metal centers. Because of this, the crystal structures were refined allowing the metal centers to move from the 0,0,0 and 0,0,1/2 positions away from positional symmetry restrictions . The refinement under these conditions leads to excellent agreement factors Rwp, Rp, S , good pattern background fitting, and produced a refined structural model consistent with the crystal chemistry of nitroprussides. The studied materials are obtained as hydrates. On heating, the crystal water evolves, and below 100 °C an anhydrous phase is obtained, preserving the framework of the original hydrates. The loss of the crystal water leads to cell contraction that represents around 2% of cell volume reduction. On cooling down from room temperature to 77 and 12 K, a slight expansion for the -M-N C-Fe-C N-M- chain length is observed, suggesting that at low temperature and reduction in the metals charge delocalization on the CN bridges takes place. For M=Fe and Co the crystal structure was also refined for the anhydrous phase at 12, 77, and 300 K. © 2007 International Centre for Diffraction Data. DOI: 10.1154/1.2700265Powder Diffraction2012-03-28T00:01:35Z2012-03-28T00:01:35Z2007-01-232013-01-16T13:26:38Z2013-01-16T13:26:38Z2013-01-16info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlePowder Diffraction 22 1 , March 2007http://hdl.handle.net/123456789/713http://www.repositoriodigital.ipn.mx/handle/123456789/11202reponame:Repositorio Digital del IPNinstname:Instituto Politécnico Nacionalinstacron:IPNeninfo:eu-repo/semantics/openAccessoai:www.repositoriodigital.ipn.mx:123456789/112022026-02-18T16:41:00Z
dc.title.none.fl_str_mv Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
title Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
spellingShingle Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
GOMEZ, A.
nitroprusside
crystal structure
porous material
Rietveld refinement,
Prussian blue analogues
title_short Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
title_full Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
title_fullStr Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
title_full_unstemmed Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
title_sort Crystal structures of cubic nitroprussides: M†Fe„CN…5NO‡ ·xH2O„M =Fe,Co,Ni…. Obtaining structural information from the background
dc.creator.none.fl_str_mv GOMEZ, A.
RODRIGUEZ HERNANDEZ, J.
REGUERA, E.
author GOMEZ, A.
author_facet GOMEZ, A.
RODRIGUEZ HERNANDEZ, J.
REGUERA, E.
author_role author
author2 RODRIGUEZ HERNANDEZ, J.
REGUERA, E.
author2_role author
author
dc.subject.none.fl_str_mv nitroprusside
crystal structure
porous material
Rietveld refinement,
Prussian blue analogues
topic nitroprusside
crystal structure
porous material
Rietveld refinement,
Prussian blue analogues
description A new structural model is proposed for cubic nitroprussides and the crystal structure for the complex salts of Fe 2+ , Co 2+ , and Ni 2+ refined in that model. In cubic nitroprussides the building unit, Fe CN 5NO 2−, and the assembling metal M=Fe2+,Co2+,Ni2+ , have 3 4 occupancy with three formula units per cell Z=3 . This leads to certain structural disorder and to different local environments for the outer metal. The crystallographic results are supported by the Mössbauer and infrared data. The XRD powder patterns, index in a cubic cell Fm3m space group , show a sinuous background because of diffuse scattering from positional disorder of the metal centers. Because of this, the crystal structures were refined allowing the metal centers to move from the 0,0,0 and 0,0,1/2 positions away from positional symmetry restrictions . The refinement under these conditions leads to excellent agreement factors Rwp, Rp, S , good pattern background fitting, and produced a refined structural model consistent with the crystal chemistry of nitroprussides. The studied materials are obtained as hydrates. On heating, the crystal water evolves, and below 100 °C an anhydrous phase is obtained, preserving the framework of the original hydrates. The loss of the crystal water leads to cell contraction that represents around 2% of cell volume reduction. On cooling down from room temperature to 77 and 12 K, a slight expansion for the -M-N C-Fe-C N-M- chain length is observed, suggesting that at low temperature and reduction in the metals charge delocalization on the CN bridges takes place. For M=Fe and Co the crystal structure was also refined for the anhydrous phase at 12, 77, and 300 K. © 2007 International Centre for Diffraction Data. DOI: 10.1154/1.2700265
publishDate 2007
dc.date.none.fl_str_mv 2007-01-23
2012-03-28T00:01:35Z
2012-03-28T00:01:35Z
2013-01-16T13:26:38Z
2013-01-16T13:26:38Z
2013-01-16
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv Powder Diffraction 22 1 , March 2007
http://hdl.handle.net/123456789/713
http://www.repositoriodigital.ipn.mx/handle/123456789/11202
identifier_str_mv Powder Diffraction 22 1 , March 2007
url http://hdl.handle.net/123456789/713
http://www.repositoriodigital.ipn.mx/handle/123456789/11202
dc.language.none.fl_str_mv en
language_invalid_str_mv en
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Powder Diffraction
publisher.none.fl_str_mv Powder Diffraction
dc.source.none.fl_str_mv reponame:Repositorio Digital del IPN
instname:Instituto Politécnico Nacional
instacron:IPN
instname_str Instituto Politécnico Nacional
instacron_str IPN
institution IPN
reponame_str Repositorio Digital del IPN
collection Repositorio Digital del IPN
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,81155

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