Rapid and exothermic solid-state synthesis of metal oxyhalides and their solid solutions via energetic metathesis reactions

Abstract

Rapid solid-state metathesis reaction chemistry has been extended to the production of layered metal oxyhalide systems. This article describes the successful synthesis of crystalline BiO X ( X=Cl, I), and lanthanide oxychlorides ( LnOCl, Ln=La, Sm, Gd) from metal trihalides and Na 2O 2 in seconds. These known materials contain halide double layers separating M–O layers. Powder X-ray diffraction results on the metathesis metal oxyhalide products agree with prior literature reports. The morphological and compositional properties of the metal oxyhalide products are described. The rapid production of well-mixed paramagnetic Gd x Sm 1− x OCl solid-solution materials was achieved using physical mixtures of SmCl 3 and GdCl 3 precursors reacted with Na 2O 2. The room-temperature magnetic properties of these materials with varying compositions are also described. As expected, magnetism, unit cell parameters, and M–O vibrational bands are all dependent on metal composition in the solid-solution products and vary in an approximately linear Vegard's law fashion.