Thulium vapor pressure

Thulium is a naturally occurring rare metal that exists is very small amounts mixed with other rare-earths. It is a bright silvery metal that is malleable and ductile and can be cut easily with a knife. Its melting point is so high that it is difficult to force it into a melted state. Its vapor pressure is also high, and thus, much of the molten thulium evaporates into the atmosphere. Its melting point is 1,545°C, its boiling point is 2,950°C, and its density is 9.32g/cm. ... 

Since no accurate vapor pressure data are available for the erbium and thulium hahdes, the molar absorptivities were determined directly from a weighed amount of the respective rare-earth halides. Good results could be obtained from this method if the respective halogen, bromine, or iodine were added to the cell such that its pressure at 1000°C. was 1 atm. This procedure greatly reduced the reaction of the rare-earth... 

The shape of the curve shown in Figure 56 predicts a fairly high stability of neodymium and promethium dichlorides among the compounds with CN = 9 and dysprosium and thulium dichlorides among the compounds with CN = 7, that is, exactly those lanthanide dichlorides that (except PmCl2) not only were successfully synthesized but also were the subject of some physicochemical measurements that required heating to high temperatures. For instance, saturated vapor pressure of... 

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