Preparation of calcium oxide from chicken and goat bones through decomposition thermal at various temperatures at 400°C, 500°C, 700°C, 800°C, 900°C, 1000°C, 1100°C has been carried out. The CaO from decomposition was characterized by XRD. The results of XRD diffraction pattem shown of decomposisition thermal at 1100°C has similar XRD pattem with CaO Standard from JCPDS. The 20 values ar…