Investigations of Proton Conduction in the Monoclinic Phase of RbH2PO4 Using Multinuclear Solid-State NMR

To understand the nature of the high-temperature phase transition and the origin of proton conductivity in rubidium dihydrogen phosphate RbH2PO4, (RDP), we utilized variable-temperature 1H, 31P, and 87Rb MAS NMR at 11.7 and 21.1 T. The variable-temperature 1H MAS NMR spectra do not show water peaks in the temperature range of 300−400 K, which argues against a partial polymerization and/or decomposition. The 1H DQ MAS NMR spectra acquired at …