Synthesis and crystal structure of a novel lithium bismuth phosphate, Li2Bi14.67(PO4)6O14

A lithium bismuth phosphate, Li2Bi14.67(PO4)6O14, has been synthesized for the first time by the solid-state method. The crystal structure was determined by single crystal X-ray diffraction at 150 K. Li2Bi14.67(PO4)6O14 crystallizes in the monoclinic system C2/c (No. 15), with a = 30.8189(4) Å, b = 5.2691(3) Å, c = 24.5302(3) Å, β = 122.84(2)°, V = 3346.81(1) Å3 and Z = 2. The structure along the b axis consists of layers of [Bi2O2] units as the basic building block. These are separated by isolated PO4 and LiO4 tetrahedra. The oxygen co-ordination around two of the phosphorus atoms is disordered. Solid-state 7Li NMR studies confirm the presence of lithium in the structure. The material shows ionic conductivity of the order of 10−5 S cm−1 at 600 °C.