Cation mass-valence sum (CM-VS) approach to assigning OH-bending bands in dioctahedral smectites
Gates, Will (Monash University. Department of Civil Engineering)

Data:	2008
Resum:	The assignments of OH-bending bands in the infrared (IR) spectra of dioctahedral smectites (montmorillonites, ferruginous smectites, and nontronites) have been revisited using a cation mass-valence sum (CM-VS) approach to quantify octahedral cation occupancy. The CM-VS approach enabled prediction of OH-bending band positions (in wavenumbers) related to OH-sharing octahedral cation pairs that had valence sums of 4 and 5, and cation masses associated with Fe(II) and Mg. Application of rules for the relationship enabled determination of the location of OH-sharing octahedral cation pairs containing Mg and Fe(II) for which previous assignments have been considered controversial, e. g. Fe(III)Mg-OH and MgMg-OH, or for which assignments have been missing due to lack of spectroscopic evidence, e. g. AlFe(II)-OH, Fe(III)Fe(II)-OH, Fe(II)Mg-OH, and Fe(II)Fe(II)-OH. Examples of these bands from several natural ferruginous smectites and nontronites are discussed. Quantification of IR spectra was used to develop a better understanding of the octahedral cation occupancy of this important class of Fe(III)-enriched smectites. While Fe(II) contents may be somewhat overestimated by the IR technique, those for four of the six ferruginous smectites studied here agree well with data from Mössbauer spectroscopy.
Drets:	Aquest material està protegit per drets d'autor i/o drets afins. Podeu utilitzar aquest material en funció del que permet la legislació de drets d'autor i drets afins d'aplicació al vostre cas. Per a d'altres usos heu d'obtenir permís del(s) titular(s) de drets.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Cation mass ; Cation pairs ; Infrared spectroscopy ; Octahedral ; Smectite chemistry ; Valence sum
Publicat a:	Clays and Clay Minerals, Vol. 56, Núm. 1 (2008) , p. 10-22, ISSN 1552-8367

DOI: 10.1346/CCMN.2008.0560102

13 p, 1.8 MB  Accés restringit a la UAB

El registre apareix a les col·leccions:
Articles > Articles de recerca
Articles > Articles publicats