SYNTHESIS AND CRYSTAL STRUCTURE OF A NEW LITHIUM NICKEL FLUOROPHOSPHATE Li2[NiF(PO4)] WITH AN ORDERED MIXED ANIONIC FRAMEWORK

摘要

A new lithium nickel fluorophosphate Li2[NiF(PO4)] has been synthesized. It crystallizes in the orthorhombic system with unit-cell parameters a=10.473(3) angstroms, b=6.2887(8) angstroms, c=10.846(1) angstroms, and space group Pnma (no. 62), Z=8. Its structure has been determined from single-crystal XRD data and refined to a conventional R=0.030 (R=0.033) for 647 reflections with I>3sigma(I). The structure is built of infinite chains of a rutile type of NiO4F2 octahedra running along the b direction further joined together by isolated PO4 tetrahedra by sharing corners. This 3-D framework delimits channels parallel to the b direction where the Li+ ions lie. This compound is characterized by a rigorous O-F ordering. 15 refs.