In chemistry, a salt is a chemical compound composed of cations (positively charged ions) bound to anions (negatively charged ions). They are typically the product of a chemical reaction between a base and an acid, the base contributing the cation and the acid contributing the anion.
A familiar example is table salt, in common usage simply called salt. It is the specific salt sodium chloride, and is described thoroughly in that article. Its formula is NaCl and it is the product of the base sodium hydroxide, NaOH and hydrochloric acid, HCl. Table salt is derived by purification from sea salt, or by mining directly from pockets of salt trapped in impervious rock (see Salt mine).
In general, salts are ionic compounds which form crystals. They are usually soluble in water, where the two ions separate. Salts typically have a high melting point, low hardness, and low compressibility. If molten or dissolved in water, they conduct electricity.
Salts are named according to their constituent ions. The cationic components, often metal ions or ammonium, are given first, followed by the anionic components. Cations are often named according to the their conjugate acid:
- acetates are the salts of acetic acid
- carbonates are the salts of carbonic acid
- chlorides are the salts of hydrochloric acid
- cyanates are the salts of cyanic acid
- nitrates are the salts of nitric acid
- nitrites are the salts of nitrous acid
- phosphates are the salts of phosphoric acid
- sulfates are the salts of sulfuric acid