The elastic constants of triclinic TlH3(C2O4)2 · 2 H2O and their temperature derivatives have been determined from ultrasonic resonance frequencies of thick plane-parallel plates. The elastic constants differ only slightly from those of the isotypic potassium salt. However, a distinct difference in respect to the deviation from Cauchy's relations occurs similar to the situation in many other isotypic potassium and thallium salts. The thermoelastic constants show an almost isotropic behaviour in contrast to the very large elastic anisotropy.
Zeitschrift für Kristallographie – Crystalline Materials offers a place for researchers to present results of their crystallographic studies. The journal includes theoretical as well as experimental research. It publishes Original Papers, Letters and Review Articles in manifold areas of crystallography.