Amorphous aluminum phosphates of various compositions were prepared by a precipitation reaction, using aqueous solutions of NaH2PO4, Al(NO3)(3), and NH4OH as reagents, The resulting solids were chemically characterized and tested in order to observe their capability to undergo closed-pore formation under heating at high temperatures (above 400 degrees C), The formation of closed pores improves the particles’ light-backscattering power, making them useful as white pigments.