A Single Crystal Neutron Diffraction Determination of the Hydrogen Position in Potassium Bifluoride

Neutron diffraction measurements on KHF2 single crystals show that the hydrogen atom occupies the central position, within 0.1A, in the linear F–H–F ion. The data also indicate asymmetry in thermal motion, which suggests that the bifluoride ion undergoes rotatory oscillation with appreciable amplitude. The study demonstrates the usefulness of single crystal neutron diffraction data for crystal structure determination.