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A Thermodynamic Understanding of Clay-Swelling Inhibition by Potassium Ions


  • The authors acknowledge financial support from the National Science Foundation of China (no. 40373024), and the kind help of Dr. T. J. Tambach from the Van't Hoff Institute for Molecular Sciences, Prof. H. Q. Zhou, Prof. J. Ma, Dr. X. Wang, and Dr. X. Zhang.


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Caged: Potassium ions are trapped in coordination cages composed of surface hexagons and water molecules in a smectite interlayer (see picture; blue K, red O, white H). This microstructure leads to a striking stability of the single-layer K-smectite hydrate and inhibits further swelling of the clay.