Co0.5Fe0.5(H2PO4)2·2H2O is synthesized by simply stirring a suspension of H3PO4, CoCO3, and Fe in acetone/water for 10 min at ambient temperature. This method is a simple, rapid, cost-effective, and environmental friendly route. Thermal transformation of the prepared powder to CoFeP 4 O 12 is monitored by TG/DTG/DTA and DSC. Co 0.5 Fe 0.5 (H 2 PO 4 ) 2 ·2H 2 O and CoFeP4O12 crystallize in the monoclinic space group P21/n and C2/c, respectively. Both compounds are superparamagnetic at room temperature. -(BOONCHOM*, B.; DANVIRUTAI, C.; VITTAYAKORN, N.; Solid State Sci. 13 (2011) 1, 77-81, http://dx.