P. Toulmin III
P. B. Barton Jr.
1964
<p>A new method for the determination of the fugacity of sulfur in laboratory systems consists of visual observation of the development and decomposition of a sulfide tarnish phase on silver-gold alloy (electrum) of precisely known composition. The alloy system is calibrated against pure sulfur. The method has the following advantages: simple apparatus; ability to cover a large range of fugacity of S<sub>2</sub>; ability to cover a large temperature range by permitting runs of long duration; ability to tolerate other components in the gas phase; and ease of recovery of the quenched charges for determinations of phases and compositions. Results obtained by the electrum-tarnish method are in satisfactory agreement with those obtained by other workers for the f<sub>s2</sub><span> </span>vs.<span> </span><i>T</i><span> </span>curves for the assemblage Ni<sub>(1–<i>x</i>)</sub>S + NiS<sub>2</sub>. The electrum-tarnish method shows promise for investigating many other reactions.</p><p>Univariant reactions studied by this method can be represented as lines forming a genetic grid in terms of the environmental parameters f<sub>s2</sub><span> </span>and<span> </span><i>T</i>, The slopes of such lines can yield valuable thermodynamic data for the phases involved, but activity coefficients must be known for phases of variable composition.</p>
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10.1016/0016-7037(64)90082-1
en
Elsevier
The electrum-tarnish method for the determination of the fugacity of sulfur in laboratory sulfide systems
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