³⁹K nuclear magnetic resonance in a KHSO₄ single crystal

The ³⁹K NMR in a KHSO₄ single crystal grown by the slow evaporation method was investigated by employing a Bruker FT NMR spectrometer, and the ³⁹K quadrupole coupling was determined from the angular dependences of the four ³⁹K±1/2↔∓1/2 central NMR transitions. There are two sets of crystallographically inequivalent K⁺ ions: K(1) and K(2). From these angular dependences, all lead to different values for the quadrupole coupling constant and asymmetry parameter: e²qQ/h = 1.06±0.07 MHz, η = 0.58±0.05 for the K(1) ion, and e²qQ/h = 1.45±0.07 MHz, η = 0.85±0.05 for the K(2) ion. The EFG tensors of K(1) and K(2) are asymmetric and the orientations of the principal axes of the EFG tensors do not coincide for the K(1) and K(2) sites. The K(1) ions surrounded by nine oxygen atoms are high in symmetry, while K(2) ions surrounded by nine oxygen atoms show low symmetry.