Mixed valences system in cobalt iron cyanide. Microporous structure stability

Divalent transition metal hexacyanoferrates( III) have a microporous framework appropriate for separation and storage of small molecules. The nature of such porous framework is found in the existence of systematic vacancies of the building unit, the hexacyanoferrate octahedral block, [Fe(CN)6], in t...

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Detalhes bibliográficos
Autores: REGUERA, L., REGUERA, E., BALMASEDA, J., RODRIGUEZ HERNANDEZ, J., YEE-MADEIRA, H.
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2007
País:México
Recursos:Instituto Politécnico Nacional
Repositorio:Repositorio Digital del IPN
OAI Identifier:oai:www.repositoriodigital.ipn.mx:123456789/11144
Acesso em linha:http://hdl.handle.net/123456789/657
http://www.repositoriodigital.ipn.mx/handle/123456789/11144
Access Level:acceso abierto
Palavra-chave:Prussian blue analogue
Porous material
Porous framework
Adsorption
Descrição
Resumo:Divalent transition metal hexacyanoferrates( III) have a microporous framework appropriate for separation and storage of small molecules. The nature of such porous framework is found in the existence of systematic vacancies of the building unit, the hexacyanoferrate octahedral block, [Fe(CN)6], in the material structure. The relatively low thermal stability appears to be the main limitation of these materials for such applications. In the as-synthesized material the available free volume is occupied by water which, can be removed by moderated heating but always involving decomposition of at least a small sample fraction. For cobalt a unique behavior has been observed. The heating of cobalt(2+) hexacyanoferrate( III) leads to an inner charge transfer to form the mixed valences Co(2+)Co(III) hexacyanoferrate(II,III) system.