Hydrogen isotherms for LaNi(sub 4.6)M(sub .04)alloys where M=Group 4A elementsHydrogen isotherms have been measured for activated LaNi(sub 4.6)M(sub 0.4) alloys from 300 K to 473 K or 493 K, where M= Si, Ge, Sn. Thermodynamic parameters have been obtained from the isotherms using van't Hoff plots for hydride decomposition.