Undoped and Eu3+ doped monohydrate strontium oxalate samples were precipita
ted under ultrasound and conventional stirring and were heated at different
temperatures. All samples were characterized by X-ray powder diffraction (
XDR), infrared spectra (IR) and scanning electron microscopy (SEM). Monohyd
rate, dehydrate oxalates and carbonate particles are ellipsoids indicating
a topotatic process. Particle size decrease is observed when ultrasound sti
rring and europium. doping are used and rehydration of strontium oxalate re
sults in uniform hexagonal particle shape. An oxide and carbonate mixture i
s obtained from oxalates treated at 1050 degreesC and its suspension in wat
er undergoes incomplete hydrolysis. The products from this incomplete hydro
lysis present dendrite shape particles only when the former is precipitated
under ultrasound stirring. In this process, surface energy is important fo
r particle dispersion and ultrasound supplies activation energy to oxalate
precursor. (C) 2001 Elsevier Science Ltd. All rights reserved.