Standard enthalpies of formation of some lutetium alloys by high-temperature direct synthesis calorimetry

Abstract

The standard enthalpies of formation for some lutetium alloys in the binary systems Lu-X (where X=C, Si, Ge, Sn, B, Al) have been determined by direct synthesis calorimetry at 1473±2 K. The following values of ΔH0f in kJ g.atom−1 are reported: LuC2 −26.7±1.8; LuSi −78.3±2.1; Lu5Ge3 −73.8±1.5; Lu5Sn3 −73.6±1.4; LuB2 −29.8±0.9; LuAl2 −52.6±3.0; GdSi = −75.6±2.3. The results are compared with some earlier experimental data derived from e.m.f. or mass spectrometric measurements, with predicted values from Miedema's semi-empirical model and with reported calorimetric data for the corresponding compounds of some early lanthanide elements.