Abstract
The three intermediate compounds of the Au–Pb system were synthesised by melting the pure components in suitable proportions and annealing at a temperature just below their melting point. Their structural states were verified by X-ray studies.
The enthalpy of formation of the compounds was measured by dissolution calorimetry (drop method) at 650K in liquid lead using a high temperature Tian–Calvet calorimeter. The measurements lead to:
h
f
(
Au
0.667
Pb
0.333,
cr,
298
K)=−3.1
kJ
mol
−1
h
f
(
Au
0.333
Pb
0.667,
cr,
298
K)=−3.2
kJ
mol
−1
h
f
(
Au
0.25
Pb
0.75,
cr,
298
K)=−1.6
kJ
mol
−1