YH3and YD3: Heat Capacities and Thermodynamic Functions from 15deg; to 350deg;K and Infrared Absorption Spectra

摘要

The heat capacities of YH3and YD3were determined in an adiabatic calorimeter from 15deg; to 350deg;K. The heat capacity, entropy, enthalpy, and Gibbs freehyphen;energy function for YH3at 298.15deg;K are 10.363plusmn;0.021 cal degmdash;1molemdash;1, 10.019plusmn;0.020 cal degmdash;1molemdash;1, 1613.3plusmn;3.2 cal molemdash;1, and mdash;4.608plusmn;0.009 cal degmdash;1molemdash;1, respectively. The corresponding quantities for YD3are 13.727plusmn;0.028, 12.028plusmn;0.024, 2024.8plusmn;4.0, and mdash;5.237plusmn;0.010.The infrared absorption spectra of YH3and YD3were taken in the range 400 to 4000 cmmdash;1. Maxima in the absorption bands of YH3were observed at 1295, 920, and 640 cmmdash;1and in the absorption bands of YD3at 1295/radic;2, 920/radic;2, and 640/radic;2 cmmdash;1. A reasonable assignment of these frequencies to Ymdash;H and Ymdash;D vibrations satisfactorily accounts for the difference between the heat capacities of YH3and YD3in the temperature range 50deg; to 350deg;K. The lattice parameters as determined by xhyphen;ray diffraction for the hexagonal closehyphen;packed trihydrides werea0= 3.672plusmn;0.002 Aring; andc0= 6.625plusmn;0.018 Aring; for YH3anda0= 3.659plusmn;0.002 Aring; andc0= 6.586plusmn;0.019 Aring; for YD3.