Darstellung und Eigenschaften von Ca2AsBr, Sr2AsCl und Ca3AsBr3.

Abstract

Dark-brown Ca2AsBr and yellow-green Ca3AsBr3 were prepared by reaction of Ca, As, and CaBr2 at 900-1000°C and 760-800°C resp., dark-violet Sr2AsCl from Sr, As, and SrCl2 at 900-1000°C. Ca2AsBr possesses an extended homogeneity range (Ca2AsBr to Ca2.5AsBr2), Sr2AsCl only a narrow one; Ca3AsBr3 is a stoichiometric compound. In contrary to Ca2AsBr Ca3AsBr3 is not stable at 1000°C. Analytical results, densities, and lattice constants of the phases are given.