A rapid synthesis of cobalt cyclotetraphosphate Co2P4O12 at low temperature

The cobalt cyclotetraphosphate, Co2P4O12, was synthesized by evaporating a mixture of cobalt chloride hexahydrate, phosphoric acid and water at 70 °C, with further calcinations at 400 °C, 500 °C and 600 °C for 3 h. XRD results indicated that the Co2P4O12 compounds obtained had only monoclinic phase with space group C2h6 (Z=4). From FT-IR spectra, vibrational modes corresponding to internal vibrations of the P4O124− anion were identified. The morphologies and crystallite sizes for the Co2P4O12 obtained from SEM data and X-ray line broadening showed non-uniform particles and 37–68 nm, respectively. All characterization methods showed that the monoclinic phase of Co2P4O12 could be synthesized at the low temperature of 400 °C with short time consumption. The temperature was about 400 °C lower than that used in the previous synthesis method with CoCl2 as reactant, and resulted in a cost-, energy-, and time-saving method.