Preparation of Single Crystals of Barium Azide

Abstract

THE need for large, optically clear crystals of barium azide of high purity for research studies has been realized for some time. It was first necessary to obtain pure barium azide powder to satisfy the requirements necessary for obtaining optically clear crystals. A method for preparing high-purity barium azide powder was developed at the Explosives Research Laboratory by Reitzner and Manno1. In this method, dry gaseous hydrogen azide was made to react with spectral grade barium carbonate in aqueous suspension. Using spectral grade acetone, barium azide was precipitated from this reaction. Table 1 gives the elemental impurities found in BaCO3 and BaN6 in parts per million (atomic) and indicates that even such ‘spectroscopically pure’ materials contain many impurities. The results of this analysis were obtained from Battelle Memorial Institute by mass spectrographic techniques. An investigation was then undertaken to develop a technique for growing optically clear seed crystals of barium azide from which larger crystals could be obtained.