Crystal Structure of LiH2PO4 Studied by Single-Crystal Neutron Diffraction

Abstract

Structure of a LiH2PO4 (LDP) single crystal has been studied at room temperature and at 100 K by means of neutron diffraction. The LiO4 tetrahedra in LDP are linked by vertices forming chains along the a-axis, and a three-dimensional network is formed by PO4 groups connected by two different hydrogen bonds. The Li+ ions in this structure were found to be quite immobile in spite of their very light mass; The very high proton conductivity in the system may have directly to do with the relatively weak hydrogen bonds and the relatively long interoxygen distances facilitating reorientation of the proton acceptor complexes, rather than with the Li+ ionic motions.