Determination of heats of formation of praseodymium antimonides

Abstract

A systematic investigation of the heats of formation in the Pr--Sb system has been performed using a small-furnace, isoperibolic calorimeter. The compositions and the equilibrium states of the samples have been checked by metallographic and X-ray analyses. The following values have been found for the various compounds (kJ/g atom -t-2): Pr2Sb: --99; Pr~Sb3: --112; PraSb3: --120; PrSb: --126; PrSb2: --97.The data available (both the results obtained in this work and those already known) are discussed briefly and related to the possible shape of the phase diagram.During a systematic investigation of compounds and alloys of the rare earths, we recently reported on the heats of formation of gadolinium bismuthides [1 ] and cerium antimonides [2].In this work we have studied the heats of formation of the Pr-Sb compounds.The Pr-Sb system

Thermodynamic Properties of Solid Binary Antimonides

“…Direct-reaction calorimetry is also a popular method of measuring Δ H ° for antimonides. The formation of some antimonides is sufficiently exothermic that these experiments can be conducted by heating a mixture of the elemental powders in a sealed calorimeter and measuring the enthalpy generated by the reaction. − In a few cases, the calorimetric effect of adding antimony or the second element to an antimonide melt has been used to calculate enthalpies of formation. − This may be useful in studying less exothermic antimonide compounds.…”

“…Most of the thermodynamic studies of rare-earth antimonides have been performed by one of four groups. The first is a group at the University of Genoa, who used an isoperibol calorimeter to perform direct-reaction measurements of Δ H ° 300 for numerous compounds. − ,,,− Chua and Pratt also used direct-reaction calorimetry to determine Δ H ° for ScSb, YSb, LaSb, and LuSb; comparison of their results with those of the Genoa group shows sporadic agreement.…”

Gd–Sb system: standard enthalpies of formation of solid alloys and crystal structure of Gd16Sb39

“…On the basis of the data obtained by calorimetric methods, the following values of the standard enthalpies of formation may be indeed considered (kJ/mol of atoms, room temperature): LaSb: À1312 [23]; CeSb: À126.42 [24]; PrSb: À1262 [25]; NdSb: À1232 [26]; SmSb: À1222 [27]; GdSb: À1202 (this work); DySb: À1142 [1]; ErSb: À1114 [2].…”