抄録
The thermal reaction of a cadmium (II) oxide-ammonium dihydrogenphosphate mixture, with the CdO/NH4H2PO4 molar ratio of 1/2, was carried out in a stream of nitrogen gas. It gave cyclo-tri-and cyclo-tetraphosphates most abundantly at 400°C and at 450°C, respectively. When urea was added to the mixture, the formation temperature of cyclo-tetraphosphate was reduced to 400°C. And the urea/CdO/NH4H2PO4 mixing molar ratio of 1/1/2 was optimum for an increase in its amount. However. the addition of urea was not effective for the formation of cyclo-triphosphate.
