Physics
Scientific paper
Nov 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996gecoa..60.4279s&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 60, Issue 21, pp.4279-4283
Physics
1
Scientific paper
In following up a recent proof of a structural substitution of octahedral Fe III by V III and Cr III in synthetic geothite, the same substitution was now recorded in geothites and hematites from lateritic crusts. Substitution up to 0.018 mole mole -1 V/V + Fe is shown by congruent dissolution of Fe and V and by the presence of Fe 2+ equivalent to structural V in an acid digest. On heating the samples up to 800°C, homogenous distribution of V disappeared; i.e., V is ejected from the structure of iron oxides and oxidized to form crystalline FeVO 4 (shown by XRD). As a consequence, congruent dissolution no longer takes place as V dissolved rapidly and independently of Fe. Chromium also dissolved congruently with Fe but was not ejected from the structure on heating up to 800°C. Thermodynamic considerations, taking the standard redox potential of the Fe II /Fe III couple adsorbed to iron oxide into account, reveal that iron oxides, formed in a partly anoxic environment, may incorporate V III . Thus, as in clay minerals, V III may be used as a redox-indicator for a former anoxic environment.
Pfab G.
Schwertmann U.
No associations
LandOfFree
Structural vanadium and chromium in lateritic iron oxides: Genetic implications does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Structural vanadium and chromium in lateritic iron oxides: Genetic implications, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structural vanadium and chromium in lateritic iron oxides: Genetic implications will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1148124