⁵⁷Fe-M?ssbauer spectroscopy on natural eosphorite-childrenite-ernstite samples

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• 作者：Geraldo Magela da Costa ; Ricardo Scholz ; Joachim Karfunkel ; Vladimir Bermanec and M¨¢rio Luiz de S¨¢ Carneiro Chaves
• 关键词：Eosphorite ; Childrenite ; Ernstite ; Pegmatite ; Mö ; ssbauer spectra ; Brazil
• 刊名：Physics and Chemistry of Minerals
• 出版年：2005
• 出版时间：February 2005
• 年：2005
• 卷：31
• 期：10
• 页码：714-720
• 全文大小：517 KB

文摘

Samples of the eosphorite-childrenite [(Mn2+, Fe2+)AlPO₄(OH)₂H₂O] series from Divino das Laranjeiras and Araçuaí (Minas Gerais State) and Parelhas (Rio Grande do Norte State) pegmatites have been investigated by X-ray diffraction, microprobe analysis and Mössbauer spectroscopy at 295 and 77 K. The Mössbauer spectra of ernstite [(Mn2+, Fe3+)AlPO₄(OH)_2-xO_x] showed the existence of ferric ions in both A and B sites, whereas ferrous ions seem to be located exclusively in the A site. Nonoxidised samples show ferrous ions located in both sites, and no Fe3+ could be detected. The interpretation of the Mössbauer spectra of both, oxidised and nonoxidised samples, is difficult because the hyperfine parameters of these minerals are rather similar, rendering it difficult to make proper site assignments.