Data/hora: 29/05/2024 08:15:56

Biblioteca(s): 	Embrapa Pantanal.	
Data corrente: 	08/06/1995	
Data da última atualização: 	08/06/1995	
Autoria: 	BIGHAM, J. M.; GOLDEN, D. C.; BOWENS, L. H.; BUOL, S. W.; WEED, S. B.	
Título: 	Iron oxide mineralogy of well-drained ultisols and oxisols: I. Characterization of iron oxides in soils clays by Mossbauer spectroscopy, X-ray diffractometry, and selected chemical techniques.	
Ano de publicação: 	1978	
Fonte/Imprenta: 	Soil Science Society of American Journal, v.42, n.5, p.816-824, 1978.	
Idioma: 	Inglês	
Conteúdo: 	The iron oxides in subsoil clays (<0.2 um) from five North Carolina Ultisols and two Brazilian Oxisols were analyzed by Mossbauer spectroscopy, X-ray diffractometry, and selected chemical techniques. Goethite and hematite were identified as the dominant crystalline iron oxides in these clays. Partial substitution of AI(III) or other nonmagnetic ions for Fe(III) in the oxide structures caused reduced unit cell dimensions and subnormal effective internal magnetic fields. All samples exhibited strong superparamagnetic relaxatgion, a collapse of the Mossbauer magnetic splitting at ambient temperatures due to the ultrafine size of the oxide particles. Neglible amounts of iron were solubilized with acid ammonium oxalate; however, the Ultisol clays did contain significant amounts of silicate and/or interlayer iron that was not extractable with dithionite-citrate-bicarbonate.	
Palavras-Chave: 	Aluminous goethite; Mossbauer effect; Nuclear gamma resonance.	
Thesagro: 	Solo.	
Thesaurus Nal: 	hematite; soil.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Pantanal (CPAP)	
Exemplares: 	CPAP - (28208-1) - ADD - SP - -- - SP0081 -  - 0081 - DIS