Isostere

As isosteres two molecules or ions in chemistry refers to the same number and arrangement of atoms, and possess much the same valence electrons and the same total charge. The charge is different, so only the particles are isoelectronic. If only the number of valence electrons is equal, it is called isoelectronic.

Isosteric compounds often have very similar physical properties, so you can often draw conclusions from known to unknown compounds isosteric compounds. This principle has also kept in pharmaceutical chemistry in the search for new drugs feeder. Here, the isosteric is also called bioisosterism.

Examples

Examples are:

Isosteric compounds can find by a replaced by two atoms of any compound by an atom from a higher order group X of the periodic table and the other by an atom of a by x lower groups of the periodic system. For Example 1, this means that nitrogen is in group 15, carbon is in group 14 (15-1 ), oxygen in group 16 (15 1).

History

The term was coined by Irving Langmuir isosterism 1919 and extended by Emil Erlenmeyer on biologically active substances.

The isosteric should not be confused with the allostery or with the term " isosteres " of physical chemistry.