Titanium dioxide nanoparticles with dimensions less than 15 nm were synthesized in room temperature conditions by Iranian researchers from Semnan University. In this synthesis, nanoparticles with size of 5 nm were observed too. There are different methods to produce this nanopowder, including milling, hydrolysis, vapor phase reactions, sedimentation, sol-gel, and thermal-aquatic methods. Titanium dioxide (TiO2) has two general structures of anatase and rutile, which have numerous applications in engineering purposes. “The aim of the research was to synthesize titanium dioxide nanopowder at nanometric scale in room temperature. We succeeded in the production of nanoparticles with the size of less than 15 nm in room temperature,” Milad Dalvandi, one of the researchers, stated. Dalvandi explained the results of the research, and said, “Particles size distribution is less significant in this chemical method to produce nanopowder, to the extent that we obtained nanoparticles less than 5 nm in size by precisely controlling the experiment conditions. The synthesized powders have spherical and almost regular shape from morphological point of view. The reason is the high stability of the sol prepared in the beginning of the experiment, which is caused by chemical and physical stability of the initial sol. PH value and its variations and calcinations temperature had greater effect on the size of titanium dioxide nanoparticles in comparison with solution concentration and calcinations time. As the molar ratio of acid and the pH value increased, growth was observed in rutile phase. The rate of rutile formation increased as the molar ratio increased too.” Results of the research have been published in details in April 2013 in Journal of Sol-Gel Science and Technology, vol. 66, issue 1, pp. 68-72.