Looking into the future of hybrid glasses

Glasses are typically formed by melt-quenching, that is, cooling of a liquid on a timescale fast enough to avoid ordering to a crystalline state, and formerly thought to comprise three categories: inorganic (non-metallic), organic and metallic. Their impact is huge, providing safe containers, allowing comfortable and bright living spaces and even underlying the foundations of modern telecommunication. This impact is tempered by the inability to chemically design glasses with precise, well-defined and tunable structures: the literal quest for order in disorder. However, metal-organic or hybrid glasses are now considered to belong to a fourth category of glass chemistry. They have recently been demonstrated upon melt-quenching of coordination polymer, metal-organic framework and hybrid perovskite framework solids. In this Review, we discuss hybrid glasses through the lens of both crystalline metal-organic framework and glass chemistry, physics and engineering, to provide a vision for the future of this class of materials.