Preparation of calcium oxide from Portunus pelagicus through thermal decomposition for 3 hours at various temperature 700 °C, 800 °C, 900 °C, 1000 °C, and 1100 °C. The calcium oxide from decomposition was carried out and characterized by X-Ray Diffractometer (XRD), FT-IR spectrophotometer and SEM-EDX analyses. The result of XRD show decomposition Portunus pelagicus at 1000 °C have diffrac…