On the Precipitation of NH4CI from the Vapour

Abstract
If NH3(g) and HCl(g) diffuse from opposite ends into an air filled glass tube, one may observe discrete precipitation bands of the product NH4Cl(s) on the walls. This phenomenon has been interpreted in the literature as „periodic”︁ precipitation in the sense of Liesegang. In this paper it is shown that these bands are not Liesegang bands, but stem from slight temperature oscillations in the storage vessels. If these oscillations are prevented, the precipitate appears as a continuous layer.