Effect Of Iron On The Structure, Intrinsic Electric Dipole And Pyroelectric Properties Of Tourmaline

Tourmaline was widely used in environmental protection, Chemical industry and other areas due to it's pyroelectric properties, spontaneous polarization, infrared radiation and anion producing characteristics, and has achieved good economic results. However the mechanism of those characteristics of tourmaline was not clear, it prevented the further development and application of tourmaline functional materials .It has important theoretical significance and practical value to study the effect of chemical composition, ion valence and structure on the pyroelectric properties of tourmaline. The paper calculate parameters of polyhedron distortion and intrinsic electric dipole by using the structural data of single crystal X-ray diffraction and explore the effect of the valence, content and distribution of iron on the structure , intrinsic electric dipole and pyroelectric properties of tourmaline.After 850℃calcined 48h and 72h, content of FeO in tourmaline reduce from 1.35% to 0.14%, intrinsic electric dipole is changed from 4.310×10-29 C·m to 5.722×10-29C·m. The pyroelectric constant of tourmaline is increased from 6.418μC (m2·k)-1 to 8.948μC (m2·k)-1.Heat treatment changed the valence and distribution of iron in tourmaline crystal structure. Part of Fe3+ is likely to occupy the position of the Z, and to form allomer with Al3+ .The Y octahedron contract and the Z octahedron expand because rAl3+