Vapor Pressures of Platinum , Iridium , and Rhodium
نویسنده
چکیده
Systematic measurements of the vapor pressure of iridium and rhodium over a wide temperatme range have not been published previously. A summary of previous estimates or observations of their normal boiling points and values of their heats of sublimation, f:..H ~ (298), is given in table l. The vapor pressure of platinum was calculated by Langmuir and .Mackay from measurements of the rate of sublimation in vacuum [5].1 Subsequently, Jones, Langmuir, and Mackay [6] adjusted these data in accordance with a revised temperature scale. Stull and Sinko used tabulated thermal functions and the adjusted data to calculate a f:..H~(298) of 134.8 kcal/mole and a boiling point of 4,100 oK [4] . Simultaneously with the present investigation, Dreger and Margrave [7] at the University of Wisconsin and Hasapis, Panish and Rosen [8] at the AVCO Corp ., Wilmington, Mass. , have been measming vapor pressmes of the pertinent substances. Dreger and Margrave measmed rates of sublimation of iridium, rhodium, and platinum samples sus-
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