TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Properties: The titanium oxide particles have 6 extension portions, which are mutually and radially extended at substantially equal spacing, and have primary particle size of 100-1000 nm. Preferred Component: The extension portions are single crystals, and exhibit a twin crystal as a whole. The extension portion has an anatase single phase. The titanium alkoxide is titanium tetraethoxide, titanium tetra isopropoxide, titanium tetra normal propoxide and/or titanium tetra normal butoxide. The titanium metal salt is titanium tetrachloride and/or titanium sulfate. Preferred Conditions: The slurry-like reaction solution having pH of 9-11 is preheated at 70-150degreesC, and heated at 120-350degreesC.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Properties: The titanium oxide particles have 6 extension portions, which are mutually and radially extended at substantially equal spacing, and have primary particle size of 100-1000 nm. Preferred Component: The extension portions are single crystals, and exhibit a twin crystal as a whole. The extension portion has an anatase single phase. The titanium alkoxide is titanium tetraethoxide, titanium tetra isopropoxide, titanium tetra normal propoxide and/or titanium tetra normal butoxide. The titanium metal salt is titanium tetrachloride and/or titanium sulfate. Preferred Conditions: The slurry-like reaction solution having pH of 9-11 is preheated at 70-150degreesC, and heated at 120-350degreesC.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The organic alkali is amine, polymeric amine, its salt and/or ammonia. Content of titanium atom in the reaction solution is 0.05-10 mol/l. EXAMPLE - Titanium tetra isopropoxide (71 g) was added to pure water (in ml) (250) cooled to 10degreesC, and stirred at 300 rpm for 1 hour. Titanium tetra isopropoxide was hydrolyzed, and became white aqueous suspension. The suspension was filtered, and washed with pure water (500). The obtained white cake-like substance and 26% tetramethyl ammonium hydroxide (1.4 g) were added to pure water, to obtain a slurry-like reaction solution having pH of 10.23 and titanium atom content of 1.25 mol/l. The reaction solution was preheated at 120degreesC for 4 hours, stirred, and heated at 270degreesC for 12 hours, to obtain aqueous suspension containing titanium oxide particles. The suspension was filtered and washed. The obtained cake was washed and dried at 120degreesC for 24 hours, to obtain pulverized titanium oxide particles of twin crystal. The titanium oxide particles consist of anatase single phase having primary particle size of 10 nm, and have particle size of 0.2-0.35 microns. A dye sensitized solar cell was formed using the titanium oxide particles having high light scattering effect. The solar cell had high energy conversion efficiency.