Synthesis, Single‐Crystal Structure, Dielectric Properties of a New Phosphate K₃Bi_6.5(PO₄)_7.5

Abstract

New potassium bismuth phosphate K 3 Bi 6.5 (PO 4 ) 7.5 has been synthesized by solid-state reaction and characterized by single-crystal X-ray diffraction. This compound crystallizes in the monoclinic system, space group C2, with a = 17.637( 8) Å, b = 6.9261(8) Å, c = 22.385(4)Å, = 104.35(2)°, and Z = 4. The crystal structure model is supported by the two methods; the charge distribution (CHARDI) and bond valence sum (BVS). The crystal structure is made up of BiO n (n = 5, 6, 7, 8) polyhedra and PO 4 tetrahedra sharing corners and edges to form a three-dimensional anionic framework. The bond valence sum energy (BVSE) model of simulation shows that the potassium atoms move along [101] direction with a zigzag pathways form with an empirical activation energy of about 1.56 eV. The dielectric properties are carried out at room temperature and show high permittivity values with low dielectric loss.