Sieverts' law

Sieverts' law can be readily rationalized by considering the reaction of dissolution of the gas in the metal, which involves dissociation of the molecule of the gas. For example, for nitrogen:

N₂ (molecular gas) ⇌ 2 N (dissolved atoms)

For the above reaction, the equilibrium constant is

${\displaystyle K={\frac {c_{\text{at}}^{2}}{p_{\text{mol}}}},}$

where:

c_at is the concentration of the dissolved atoms into the metal (in the case above, atomic nitrogen N),

p_mol is the partial pressure of the gas at the interface with the metal (in the case above, the molecular nitrogen N₂).

Therefore,

${\displaystyle c_{\text{at}}={\sqrt {Kp_{\text{mol}}}}.}$

• Henry's law
• Graham's law