Synthesis Method Experimental.Titanium tetrafluoride aqueous solution(varying in concentra- tion between 2.67 and 5.33 mM)and hydrofluoricacid(10 wt%)were used as the precursor and the crystallographic controlling agent,respectively,to prepare anatase TiO2 single crystals.The reaction was carried out in a Tefon-lined autoclave at 180C for 2 to 20 h. TiO,precursor:TiF Source of F:TiF4Synthesis Method TiO2 precursor: TiF4 Source of F: TiF4