Titanium exists in two allotropic forms, one of which is a dark gray, shiny metal. The other allotrope is a dark gray amorphous powder. The metal has a melting point of 3,051°F (1,677°C), a boiling point of 5,931°F (3,277°C), and a density of 4.6 g/cm3. At room temperature, titanium tends to be brittle, although it becomes malleable and ductile at higher temperatures. Chemically, titanium is relatively inactive. At moderate temperatures, it resists attack by oxygen, most acids, chlorine, and other corrosive agents.