Sieverts’ law

https://doi.org/10.1351/goldbook.15358
Solubility of a diatomic gas in a molten metal is proportional to the square root of the partial pressure.
Notes:
  1. The law follows from the solubility constant for equilibrium dissolution of an ideal diatomic gas \(\ce{X2}\) in a metal \(\ce{M}\) to form an ideal solution of dissociated atoms: \[\ce{X2(g) <=> 2X(M)}\] for which, and for dilute solutions of the gas, \[K_{{\rm{s}},x} = a(\ce{X},\ce{M})^{2}/a(\ce{X2},{\rm{g}}) \approx x(\ce{X},\ce{M})^{2} p^{_{^⦵\!}}/p (\ce{X2},\rm{g})\] where \(x(\ce{X},\ce{M})\) is the solubility of the gas in the molten metal expressed as a mole fraction of \(\ce{H\mbox{-}atoms}\). The solubility constant \(K_{\rm{s},x}\) is called the Sieverts constant.
  2. Other forms of the solubility constant are common, especially in terms of amount concentrations or mass fractions (especially in metallurgical papers) instead of mole fractions.
Source:
PAC, 2008, 80, 233. (Glossary of terms related to solubility (IUPAC Recommendations 2008)) on page 263 [Terms] [Paper]