Abstract
A novel di-triarsenate material Na7Li0.8K0.2Co5(As3O10)(2)(As2O7)(2) has been synthesized by solid state reaction route. The structural study determined by single crystal X-ray diffraction showed the non-centrosymmetry of the structure. It crystallizes in the monoclinic system of C2 space group with the unit cell parameters: a=10.136(2) angstrom, b=8.722(2) angstrom, c=16.952(3) angstrom, beta=101.86 (2)degrees, V= 1466.9(5)angstrom(3) and Z=2. Structural analysis using Charge Distribution (CHARDI) and Bond-Valence Sum (BVS) calculations tools are envisaged to confirm the proposed structural model. The [Co2O10As3O10](infinity) chains connected to triarsentae groups toughen by CoO6 octahedra forms a 3D anionic framework showing different tunnels, where alkali ions are located. Bond Valence Site Energy (BVSE) computational model was used to simulate the alkali-ion migration pathways in the anionic framework of the studied material. It shows that the alkali ion-conduction is probably ensured by sodium cations with an activation energy Ea= 0.83 eV. Only Na+ ions migration is probably along [100] direction which diffuse through an infinite 1D pathway.