4 research outputs found
Heat Capacities of Natural Antlerite and Brochantite at Low Temperature
The
investigation of a magnetic component of the heat capacity
of natural samples of copper sulfates antlerite Cu<sub>3</sub>SO<sub>4</sub>(OH)<sub>4</sub> in the temperature range below 40 K and brochantite
Cu<sub>4</sub>SO<sub>4</sub>(OH)<sub>6</sub> below 55 K has been carried
out. A regular component of the heat capacity has been calculated
from experimental data of adiabatic calorimetry. In the low-temperature
area of (0 to 55) K two peaks of magnetic heat capacity for brochantite
have been registered. The contributions of anomalous component Δ<i>S</i><sub>tr</sub> into entropy of the minerals are (11 ±
3) J·mol<sup>–1</sup>·K<sup>–1</sup> for antlerite
and (5.3 ± 1.5) J·mol<sup>–1</sup>·K<sup>–1</sup> for brochantite