Compositions of matter and methods of identifying and making compositions of matter are disclosed. Some embodiments disclose making and chemically and/or compositionally tuning superconducting hydride materials. Some embodiments disclose an apparatus for making and compositionally tuning superconducting materials. Some embodiments disclose a composition of matter including a solid hydride exhibiting superconductivity at a temperature of at least 150 kelvin at an ambient pressure below 180 gigapascals, or at a temperature of at least 261 kelvin. In one or more embodiments, the superconductor includes a covalent metal hydride having at least three different chemical elements wherein an inter-atomic distance between the hydrogen in the covalent metal hydride is in a range of 1.1-2 angstroms. In yet further examples, the superconductor is formed using molecular exchange and compression of a Van der Waals solid. In yet further examples, the superconductor comprises molecular hydrogen disposed in 1-dimensional channels. These and other embodiments are disclosed herein.