Thorium dicarbide gas ThC2 g

The mass-spectrometric measurements show similar amounts of Th(g) and ThC2(g) in the vapom aronnd 2500 K, with ThC4(g) also being present in smaller, but still appreciable amounts at the higher temperatnres. 

The agreement between all these investigations is quite good, in contrast to many other measnrements on the condensed phases in the Th-C system. From the data of Jackson et al. [1964JAC/BAR], we obtain the following eqnation  

These data are appreciably more scattered than those of [1964JAC/BAR], 

At 2640 K, where they overlap, these values differ by ca. 8.5 kJ mol, well within the uncertainty of the measurements. The paper by [1978G1N] deals mainly with the pressures of ThC3(g) although data for Reaction (X1.5) were also obtained, there is insufficient detail in the paper for them to be included in the current analysis. 

With these thermal functiorrs, a third-law treatment of the data from [1964JAC/BAR] and [1974KOH/STE] gives (ThC2, g, 298.15 K) = (784.7 + 9.2) kJ mol and (801.5 + 8.1) kJ mol respectively, where the rmcertainties do not include those from the experimental difficrrlties (conversion from ion intensities to pressures, etc.) and those in the estimated electrorric levels for ThC2(g). However, the consistent 

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