Thermal expansion of manganese carbonate

Abstract

Precision lattice parameters of manganese carbonate have been determined at different temperatures by the X-ray powder method in the temperature range 28 to 265° C. The data has been used to evaluate, by a graphical method, the two coefficients of thermal expansion,α _∥ along thec-axis andα _⊥ at right-angles to thec-axis. The temperature-dependence of the coefficients is represented by the following equations:

$$\begin{gathered} \alpha _\parallel = 22.942 \times 10^{ - 6} - 5.555 \times 10^{ - 8} T + 3.361 \times 10^{ - 10} T^2 ,{\text{ }}(1) \hfill \\ \alpha _ \bot = 0.740 \times 10^{ - 6} + 2.812 \times 10^{ - 8} T - 6.722 \times 10^{ - 12} T^2 ,{\text{ (2)}} \hfill \\ \end{gathered} $$

(1)

whereT is the temperature in ° C.