Thermophysics of the lanthanide trihydroxides II. Heat capacities from 10 to 350 K of Nd(OH) 3 and Tb(OH) 3. Lattice and Schottky contributions

Abstract

Heat capacities have been measured from near 7 to 350 K for Nd(OH) 3 and Tb(OH) 3 and the derived thermophysical properties evaluated using previously reported heat capacities at lower temperatures. At 298.15 K the values of C p R , S o R , and −{G c − H o (0)} RT are 14.15, 15.62, and 7.484 for Nd(OH) 3 and 13.72, 15.44, and 7.525 for Tb(OH) 3. The resolution of the lattice and Schottky contributions for both compounds is discussed. The Tb(OH) 3 calorimetric Schottky contribution is correlated with spectroscopically deduced energy levels for Tb(OH) 3 and Tb 3+ -doped Y(OH) 3, while that of Nd(OH) 3 is used to estimate the crystal-field splitting of the 4 I 9 2 J-manifold. The effect of temperature upon the Schottky heat capacities is discussed.