Synthesis and characterisation of novel Weberites via solid state synthesis.

Abstract

Ca2Sb2O7 is a material known for its photocatalytic behaviour and high bandgap energy. Ca2Sb2O7 exhibits an orthorhombic structure that is synthesised by solid-state reaction at high temperature. Two phases exits when Sr is doped into the Ca site, both phases consists of the Imma space group, however one phase is rich in Sr and the other phase is rich in Ca. A phase change occurs when Mn is doped into the Ca site from a weberite orthorhombic with space group imam to a trigonal with space group P3121. When doping Sr into the Ca position of Ca2- xSrxMn2Sb4O14, the phase reverts back to the orthorhombic structure from the trigonal. When Co is doped into the Ca site in Ca2- xCoxSb2O7 a phase change from orthorhombic to trigonal occurs with the space group P3121 between x = 1 - 3. Another phase change occurs at x = 2 - 4 in which a tri-rutile phase is formed.