Figure 9.

Histogram of isotopic quotients (log Q_1,2 and log Q_1,3) for 285 natural gases (Table 1). All values of Q_1,2 and Q_1,3 were calculated as described in Table 1. The arrows beneath the chart (catalytic gas) mark the positions of log Q_1,2 and log Q_1,3 for Catalytic Gases in Table 1. The vertical lines mark isotopic equilibrium constants at 300 K, log K_1,2 = 0.31259; log K_1,3 = 0.49602, and at 500 K, log K_1,2 = 0.30786; log K_1,3 = 0.49142 [37].