A liquid that dissolves another substance or substances to form a solution. Polar solvents are compounds such as water and liquid ammonia, which have dipole moments and consequently high dielectric constants. These solvents are capable of dissolving ionic compounds or covalent compounds that ionize (see solvation). Nonpolar solvents are compounds such as ethoxyethane and benzene, which do not have permanent dipole moments. These do not dissolve ionic compounds but will dissolve nonpolar covalent compounds. Solvents can be further categorized according to their proton-donating and accepting properties. Amphiprotic solvents self-ionize and can therefore act both as proton donators and acceptors. A typical example is water:
Aprotic solvents neither accept nor donate protons; tetrachloromethane (carbon tetrachloride) is an example.