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ARS Home » Research » Publications at this Location » Publication #141696
Title: LAYER CHARGE ANALYSIS: PROBLEMS AND OPPORTUNITIES

Author
item Laird, David

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/14/2002
Publication Date: 11/14/2002
Citation: LAIRD, D.A. LAYER CHARGE ANALYSIS: PROBLEMS AND OPPORTUNITIES. AGRONOMY ABSTRACTS. 2002. CD-ROM. MADISON, WI.

Interpretive Summary:

Technical Abstract: Layer charge is a fundamental property of 2:1 phyllosilicates that greatly influences most clay properties, including: cation exchange, hydration, swelling, and interactions with both natural and anthropogenic organic molecules. The structural formula and the alkylammonium method are the two primary methods of determining layer charge. Both methods have serious limitations. Accurate layer charge determinations by the structural formula method require accurate total chemical analysis of monomineralic specimens. The alkylammonium method can be used with samples having more than one mineral phase, but the alkylammonium method seriously underestimates the layer charge of high charge clays and may overestimate the layer charge of low-charge clays. Previously reported evidence of layer-charge heterogeneity based on alkylammonium interpretations is inaccurate. An empirically corrected alkylammonium approach for estimating mean layer charge is proposed.