Neutron structural investigation of the isotope effect of KHCO3

Abstract The crystal structures of KHCO 3 and KDCO 3 have been analyzed from the three-dimensional neutron-diffraction data measured in the high-temperature phase. In the space group C2/m ( Z = 4), both the structures are refined successfully with a disordered model. The final R -factors are 0.055 for KHCO 3 , and 0.047 for KDCO 3 , respectively. Fourier analysis also reveals that the proton of KHCO 3 and deuteron of KDCO 3 have two-equilibrium positions separated by 0.616(4) and 0.647(3) A, respectively.