The elastic constants of sodium chloride and rubidium chloride in the range 140-300 K

Abstract

Measurements of the adiabatic elastic constants of NaCl from 190 to 300 K and of RbCl from 140 to 300 K have been made using the `sing-around' system to an absolute accuracy of ±0·2% and with a relative accuracy of ±0·05%. The elastic constants of NaCl agree with other recent measurements. The measurements of the elastic constants of RbCl agree with other work for C ₁₁ and C ₄₄ but the variation of C ₁₂ with temperature disagrees with the other measurements. The decrease in C ₁₂ of RbCl with decreasing temperature is in accordance with the variation of C ₁₂ in other alkali chlorides. The reasons for the disagreement of the variation of C ₁₂ are examined and it is shown that the observed decrease is real.