THERMODYNAMIC PROPERTIES OF ZIRCONIUM TELLURIDES, ZRTE1.843 AND ZR5TE4

Thermodynamic properties of ZrTe1.843 and Zr5Te4 have been measured by means of solution calorimetry, drop calorimetry, and adiabatic calori metry. The thermodynamic functions for both compounds have been calcul ated. For ZrTe1.843 the following results are obtained: Delta(f)H(m) d egrees(298.15 K) = -(295 +/- 7) kJ.mol(-1), S-m degrees(298.15 K) = (1 17.48 +/- 0.12) J.K-1.mol(-1) and {H-m degrees(T) - H-m degrees(298.15 K)}/(J.mol(-1)) = 68.2251.(T/K) + 4.48851.10(-3).(T/K)(2) + 26808.0.( T/K)(-1)-20830.2. For Zr5Te4 the results are: S-m degrees(298.15 K) = (330 +/- 0.4) J.K-1.mol(-1) and {H-m degrees(T) - H-m degrees(298.15 K )}/(J.mol(-1)) = 212.069/(T/K) + 22.2143.10(-3).(T/K)(2) + 314500.(T/K ) - 66257.8. The results of the measurements on ZrTe1.843 are compared with previously reported measurements on ZrTe2. (C) 1998 Academic Pre ss Limited.