Salt class of chemical compounds whose molecules are composed of metal cation (or group of atoms with the function of a metal, such as NH+4) and acid balance (anion). Salt are products of replacement of hydrogen atoms in molecules of the acids atoms of metals or hydroxyl groups in molecules grounds acid residues.
Distinguish: medium (normal) salts formed at full replacement of hydrogen atoms acid on the atoms of metal or hydroxyl groups base on acid residues (for example, Na2CO3 - sodium carbonate, ZnCl2 - chloride zinc); acid salt - products of incomplete substitution of hydrogen atoms in molecules of the acids to atoms of metal (for example, NaHCO3 - sodium bicarbonate); main salt - products of incomplete replacement of hydroxyl groups in the molecules of the grounds on acid residues (for example, ZnOCl - primary zinc chloride); double salts containing in its composition of two different metals and the rest of the same acid [ for example, K2SO4· Al2(SO4)3 · 24H2O - potassium alum] or one of the metal and the remains of two different acids [for example СаСl2 · Sa(ОСl)2 - chlorine, or oxide, lime]; solutions of these salts behave as a mixture of two simple salts; complex salts that contain complex acid residues, such as K4[Fe)CN)6] - ferrocyanide potassium, or "yellow blood salt", or complex groups of atoms that play the role of metal, for example, [Cu (NH3)4]SO4- sulfate ameacada copper.
Salts are indispensable components of organisms, food products, are part of the medicines and widely used in technology, laboratories and at home.