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

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 BiOX (X=Cl, I), and lanthanide oxychlorides (LnOCl, Ln=La, Sm, Gd) from metal trihalides and Na2O2 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 GdxSm1−xOCl solid-solution materials was achieved using physical mixtures of SmCl3 and GdCl3 precursors reacted with Na2O2. 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.

Very rapid, filament-initiated metathesis reactions between two solids, metal trihalides and Na2O2, lead to crystalline metal oxyhalides in seconds. All products crystallize in the PbFCl structure (BiOCl shown). In addition to single metal MOCl (Bi, La, Sm, Gd) and BiOI systems, solid-solution GdxSm1−xOCl materials are also rapidly accessible using this reactive precursor strategy.Figure optionsDownload as PowerPoint slide