The PVT properties of concentrated aqueous electrolytes. IV. Changes in the compressibilities of mixing the major sea salts at 25°C

Frank J. Millero, M. Isabel Lampreia

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13 Scopus citations


The speed of sound of mixtures of the six possible combinations of the major sea salt ions (Na+, Mg2+, Cl-, and SO42-) have been determined at I=3.0 and at 25°C. The results have been used to determine the changes in the adiabatic compressibility of mixing ΔKm the major sea salts. The values of ΔKm have been fit to the equation ΔKm=y2y3I2[k0+k1(1-2y3)] where yi is the ionic strength fraction of solute i, k0 and k1 are parameters related to the interactions of like-charged ions. The Young cross-square rule is obeyed to within ±0.04×10-6 cm3-kg-1-bar-1. A linear correlation was found between the compressibility k0 and volume v0 interaction parameters (104k0=-0.24+3.999 v0, s=0.15) in agreement with out earlier findings. Estimates of the sound speeds for the cross square mixtures (NaCl+MgSO4 and MgCl2+Na2SO4) were made using the equations of Reilly and Wood. The estimated sound speeds were found to agree on the average with the measured values to ±0.36 m-sec-1.

Original languageEnglish (US)
Pages (from-to)853-864
Number of pages12
JournalJournal of Solution Chemistry
Issue number12
StatePublished - Dec 1 1985



  • MgCl
  • MgSO
  • NaCl
  • NaSO
  • Speed of sound
  • aqueous electrolytes
  • compressibility
  • sea salts

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Physical and Theoretical Chemistry

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