In situ X-ray diffraction studies on the production process of rhenium

Rhenium powder is industrially produced in a two-step reaction by reducing NH${}_4$ReO${}_4$ with hydrogen at 623 and 1173 K. In this study, both steps of the production process have been investigated via in situ X-ray powder diffraction. Up to 550 K no reaction with hydrogen can be observed. Between 550 K and 623 K poorly crystalline rhenium is formed. Crystallinity is increased during the second step at 1173 K. Annealing under hydrogen or nitrogen provides a comparable product in respect to the examined crystal and real structure parameters independent of the gas atmosphere. (© 2022 The Authors. Zeitschrift für anorganische und allgemeine Chemie published by Wiley-VCH GmbH)