Comparison of structure making/breaking properties of alkali metal ions Na+, K+ and Cs+ in water

TL;DR

This paper compares how Na+, K+, and Cs+ ions influence water's structure and ultrasonic velocity in aqueous solutions, highlighting differences in their structure-making or breaking effects through experimental and theoretical analysis.

Contribution

It provides a comparative analysis of the structure making/breaking properties of Na+, K+, and Cs+ ions in water using ultrasonic and other experimental techniques.

Findings

Na+ and K+ ions tend to structure water more than Cs+ ions.

Ultrasonic velocity varies anomalously with concentration for different ions.

The study correlates ionic effects with changes in water's hydrogen-bond network.

Abstract

The alkali metal ions in aqueous electrolyte solutions have strong influence on the surrounding network structure of water formed through hydrogen bonds. The extent of ionic perturbation to the structure of water depends on the nature of individual ions and the solute concentration. Experimental techniques like Neutron diffraction, X-ray diffraction, Raman spectroscopy, isotopic substitution study, viscosity measurements and related theoretical or simulation studies are used to understand the characteristics features of the structural changes in these solutions. Recent ultrasonic studies on aqueous solutions of NaCl, KCl and CsCl show anomalous changes in the variation of velocity (v) with increase in concentration (c) from very dilute to saturation limit. The experimental observations and theoretical or simulation studies available in the literature are considered to make a comparative study on the structure making/breaking properties of Na+, K+ and Cs+ ions in water and consequent effect in ultrasonic velocity change.