Hi Inayat, you can use the stoichiometric conversion factors to calculate oxides from molar values. For example, the specific factor for Ti is 1.6681. If you divide your TiO2 content (in wt%) derived from XRF analysis by the factor 1.6681, you get the molar Ti content. You can find the conversion factors for other elements on the website of James-Cook-University at the following link: https://www.jcu.edu.au/advanced-analytical-centre/services-and-resources/resources-and-extras/element-to-stoichiometric-oxide-conversion-factors