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Crystallization of Metal Substituted Ferrihydrites
Author(s) -
Giovanoli Rudolf,
Cornell Rochelle M.
Publication year - 1992
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.19921550517
Subject(s) - ferrihydrite , chemistry , crystallization , metal ions in aqueous solution , metal , dissolution , crystallography , inorganic chemistry , organic chemistry , adsorption
The effects of a series of divalent, first row transition elements, i.e. Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ and Zn 2+ on the crystallization of ferrihydrite have been compared. With the exception of Mn 2+ , the metal ions considered, stabilized ferrihydrite and enhanced the amount of haematite in the reaction product. The stabilizing ability of these ions could be related to the increase in covalency of these metals along the series. With more than 15 mole% divalent metal ion present, ferrihydrite transformed to a spinel phase by a dissolution/reprecipitation mechanism. These metals can replace some Fe 3+ in the structures of the crystallization products. Factors that influence the extent of isomorphous substitution are the match between the radii and charges of Fe 3+ and the substituent ions and also, the congruency of dissolution of the M/ferrihydrite coprecipitate.