short communications
A reaction cell for in situ studies of both ion-exchange and hydrothermal titration reactions has been designed and built. This cell allows the injection of reagents into a reaction mixture over time during X-ray data collection. A demonstration experiment followed the injection of Na2SO4(aq) into BaCl2(aq) to yield a time-resolved X-ray powder diffraction pattern of the precipitation of BaSO4(s).