Ship-in-a-Bottle Synthesis of High Concentration of N 2 Molecules in a Cage-Structured Electride

We report the formation of neutral nitrogen molecules in the cages of [Ca Al O ] (C12A7) framework compensated by extra-framework anions. NH treatment of C12A7 electride (C12A7: ) at 800 °C leads to the formation of N and NH species in the C12A7 cages. N and NH species in the cages are identified using the Raman spectroscopy of NH and NH -treated C12A7: . The concentration of H and N in the C12A7 cages after NH treatment is ∼10 cm . We propose a two-step mechanism, supported by density functional theory (DFT) modeling, of N incorporation into the C12A7 cages, i.e., incorporation of NH formed from decomposition of NH at C12A7: surface followed by the NH species reacting to form N molecules. Encapsulation of neutral molecules, as opposed to negatively charged species reported in C12A7 previously, offers new opportunities for trapping and storing gaseous substances in nanoporous materials.