In:
Clays and Clay Minerals, Cambridge University Press (CUP), Vol. 52, No. 2 ( 2004-04), p. 221-226
Abstract:
Ferrihydrite is a poorly crystalline Fe oxide of which 2-(XRD)line and 6-line varieties are commonly used in experiments, although species with intermediate numbers of peaks have been found in nature. To simulate nature, we synthesized two continuous series of ferrihydrites with between 2 and 6–7 peaks at room temperature in two different ways: (1) by varying the rate of hydrolysis of an Fe(NO 3 ) 3 solution (HR series); and (2) by oxidizing an FeCl 2 solution containing up to 73 mmol Si/L (Si series), both at pH 7. Mössbauer spectra at 4.2 K showed that the ferrihydrites of the HR series had a constant magnetic hyperfine field ( B hf ) at 4.2 K of 48.8 T whereas B hf in the Si series dropped from 49.4 to 46.7 T as the Si content of the ferrihydrites increased from 0 to 74.7 g/kg of Si. Temperature scans between 4 and 170 K illustrate that the magnetic order breaks down at a temperature which is lower the higher the hydrolysis rate and the Si concentration in the ferrihydrite.
Type of Medium:
Online Resource
ISSN:
0009-8604
,
1552-8367
DOI:
10.1346/CCMN.2004.0520208
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2004
detail.hit.zdb_id:
2045991-9
detail.hit.zdb_id:
221428-3
SSG:
13
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