When the chloride preparation was to be used immediately, a modified apparatus was used. The three-piece metal unit was replaced by a corresponding one-piece unit of glass attached to a valve with a glass-to-metal seal. CrOpFt.-Technical trade CrOa was vacuum dried overnight at llOo, then placed in a dry-box where all the handling of the reactants took place. Equal amounts of CrOa and CoFs were finely ground and intimately mixed. The ...