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Title: The Oxidation State of Tungsten in Iron Bearing and Iron Free Silicate Glasses: Results from W L-Edge XANES Measurements

Abstract

Knowledge of the oxidation state of W over a wide range of fO{sub 2} is critical to understanding the oxidation state of the mantle and core formation processes. W occurs as W6+ above {approx}IW-1. The transition between W{sup 4+} and W{sup 6+} occurs just below IW-1. Tungsten is important in constraining core formation of the Earth because this element is a moderately siderophile element (depleted {approx} 10 relative to chondrites) and, as a member of the Hf-W isotopic system, it is useful in constraining the timing of core formation. A number of previous experimental studies have been carried out to determine the silicate solubility and metal-silicate partitioning behavior of W, including its concomitant oxidation state. However, results of previous studies (Fig. 1) are inconsistent on whether W occurs as W4+ or W{sup 6+}. It is assumed that W{sup 4+} is the cation valence relevant to core formation. Given the sensitivity to silicate composition of high valence cations, knowledge of the oxidation state of W over a wide range of fO{sub 2} is critical to understanding the oxidation state of the mantle and core formation processes. This study seeks to measure the W valence and change in valence state over themore » range of fO{sub 2} most relevant to core formation, around IW-2.« less

Authors:
; ; ; ;  [1];  [2]
  1. (UofC)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1009018
Resource Type:
Conference
Resource Relation:
Conference: Lunar and Planetary Science XXXVIII;March 12-16, 2007;Houston, Texas
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 58 GEOSCIENCES; CHONDRITES; IRON; SENSITIVITY; METALLIC GLASSES; SILICATES; SOLUBILITY; TUNGSTEN; VALENCE; EARTH MANTLE; EARTH CORE

Citation Formats

Danielson, L.R., Righter, K., Sutton, S., Newville, M., Le, L., and NASA). The Oxidation State of Tungsten in Iron Bearing and Iron Free Silicate Glasses: Results from W L-Edge XANES Measurements. United States: N. p., 2007. Web.
Danielson, L.R., Righter, K., Sutton, S., Newville, M., Le, L., & NASA). The Oxidation State of Tungsten in Iron Bearing and Iron Free Silicate Glasses: Results from W L-Edge XANES Measurements. United States.
Danielson, L.R., Righter, K., Sutton, S., Newville, M., Le, L., and NASA). Tue . "The Oxidation State of Tungsten in Iron Bearing and Iron Free Silicate Glasses: Results from W L-Edge XANES Measurements". United States. doi:.
@article{osti_1009018,
title = {The Oxidation State of Tungsten in Iron Bearing and Iron Free Silicate Glasses: Results from W L-Edge XANES Measurements},
author = {Danielson, L.R. and Righter, K. and Sutton, S. and Newville, M. and Le, L. and NASA)},
abstractNote = {Knowledge of the oxidation state of W over a wide range of fO{sub 2} is critical to understanding the oxidation state of the mantle and core formation processes. W occurs as W6+ above {approx}IW-1. The transition between W{sup 4+} and W{sup 6+} occurs just below IW-1. Tungsten is important in constraining core formation of the Earth because this element is a moderately siderophile element (depleted {approx} 10 relative to chondrites) and, as a member of the Hf-W isotopic system, it is useful in constraining the timing of core formation. A number of previous experimental studies have been carried out to determine the silicate solubility and metal-silicate partitioning behavior of W, including its concomitant oxidation state. However, results of previous studies (Fig. 1) are inconsistent on whether W occurs as W4+ or W{sup 6+}. It is assumed that W{sup 4+} is the cation valence relevant to core formation. Given the sensitivity to silicate composition of high valence cations, knowledge of the oxidation state of W over a wide range of fO{sub 2} is critical to understanding the oxidation state of the mantle and core formation processes. This study seeks to measure the W valence and change in valence state over the range of fO{sub 2} most relevant to core formation, around IW-2.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Mar 06 00:00:00 EST 2007},
month = {Tue Mar 06 00:00:00 EST 2007}
}

Conference:
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