Micro-crystals of bismuth orthosilicate (Bi4Si3O12) were synthesized by a sol-gel method, using stoichiometric Si(OC2H5)(4), Bi(NO3)(3)center dot 5H(2)O as the precursors and acetic acid as the solvent. The calcining process of the as-dried gel was studied by total gravity/differential scanning calory (TG/DSC), X-ray diffraction (XRD) and infrared (IR) spectra. Experiments showed that single phase of Bi4Si3O12 could be obtained by sol-gel method at a calcining temperature of 900 degrees C. Phase separation in the sol-gel process was found during the calcination. (C) 2012 Elsevier B.V. All rights reserved.