Study of rhombohedral tricalcium phosphate in hexagonal crystal structure family on the sample prepared by the sol-gel route and the effect of calcination temperature

tricalcium phosphate with a rhombohedral crystal structure by utilizing natural limestone available in Indonesia. In several previous tricalcium phosphate studies using the sol-gel technique, the CaCO 3 compounds have been used as a precursor in the sol-gel route, but many studies use fabricated CaCO 3 compounds with varying levels of purity. Meanwhile, the use of CaCO 3 compounds from natural materials is rarely carried out in similar studies. Therefore, the novelty of this study is related to: 1) the use of a novel CaCO 3 material as a precursor in the sol-gel route for the sample preparation of tricalcium phosphate derived from the mineral limestone (natural raw material) in the Lumajang region, East Java, Indonesia; 2) this research study focused on the microstructure of tricalcium phosphate in the rhombohedral crystal system which is a family of hexagonal crystal structure with the level of stability of the crystal structure affected by heating temperature; and 3) the search for the potential use of the novel materials of CaCO 3 as an artificial bone bioceramic derived by a limestone mineral in Lumajang with the rhombohedral system crystal characteristics. In this focus, the rhombohedral tricalcium phosphate was prepared from limestone (CaCO 3 ) that was obtained from nature in the Lumajang district, with the use