Water is a chemical compound with the formula H₂O, consisting of two hydrogen atoms covalently bonded to one oxygen atom. Its bent molecular geometry (104.5° bond angle) and high electronegativity difference produce a strong dipole moment, hydrogen bonding, and the anomalous thermal and solvent properties on which all known life depends. Water exists naturally on Earth as solid, liquid, and gas, and covers approximately 71% of the planet's surface.