Standard enthalpies of formation of scandium alloys, Sc+Me (MeFe, Co, Ni, Ru, Rh, Pd, Ir, Pt), by high-temperature calorimetry
摘要:
The standard enthalpies of formation of scandium alloys, Sc+Me (Me=Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt) were determined by direct synthesis calorimetry at 1473 +/- 2K. The following values of DELTA(f)H(m)-degrees/(kJ g atom-1) are reported: Fe2SC, -(11.2 +/- 1.2); Co2Sc, -(32.5 +/- 2.1); CoSc2, -(26.7 +/- 1.9); Ni2SC, -(43.0 +/- 2.3); NiSc, -(44.7 +/- 2.3); RuSc, -(44.5 +/- 2.2); Rh3SC, -(51.7 +/- 1.4); RhSc, -(94.5 +/- 1.5); PdSc, -(89.3 +/- 2.2); IrSc, -(89.7 +/- 3.0); lr2SC, -(66.3 +/- 1.3); PtSc, -(104.8 +/- 5.4). The results are compared with predicted values, and with earlier data for some of the corresponding yttrium and titanium alloys.
In this novel motif, scandium atoms define infinite parallel chains of alternate trans-face-sharing cubes and pairs of square antiprisms in which each polyhedron is also centered by an M atom (M = Ru, Os). These chains are further linked into a three-dimensional structure by Sc(Te2Te4/2) octahedra. Physical property measurements show Sc14Ru3Te8 to be metallic and Pauli-paramagnetic, consistent with