The left-hand side of one of the various cross-differential relationships that can be obtained from the @G02627@ equation when only one @C01032@ (\(\mu \)) is considered as @V06600@, viz. \[(\frac{\partial E}{\partial \mu })_{T,p,\sigma }=- (\frac{\partial \mathit{\Gamma }}{\partial \sigma })_{T,p,\mu }\] where \(E\) is the potential difference, \(T\) is the temperature, \(p\) is the pressure, \(\mathit{\Gamma}\) is the @S06171@ and \(\sigma \) is the @C00988@.