Hydrolytic Condensation of Tin(IV) Alkoxide Compounds to Form Particles with Well‐Defined Morphology

The sol‐gel‐type condensation of tin(IV) ethoxide [Sn(OEt) 4 ] n (where OEt is ethoxide) under basic conditions produced spherical, submicrometer‐sized tin(IV) oxide (cassiterite) particles. Transmission electron microscopy and powder X‐ray diffraction data indicated that the grain size was approximately 20 to 30 Å (2 to 3 nm). The mixed‐metal alkoxide compound [ZnSn(OEt) 6 ] was hydrolyzed under analogous conditions to give either spherical or octahedral submicrometer‐sized crystalline particles of ZnSn(OH) 6 depending on the solvents used. These data demonstrated that the stoichiometry of the mixed‐metal alkoxide precursor was retained during condensation. Thermal treatment of ZnSn(OH) 6 resulted in crystallization of ZnSnO 3 at approximately 676°C. At neutral pH, hydrolysis of [ZnSn(OEt) 6 ] resulted in formation of a high surface area (261 m 2 /g) amorphous powder.