# Question #d7700

Jan 11, 2015

Polyatomic ions are charged chemical species composed of two or more covalently bonded atoms that are considered to act as a single unit.

The nitrite ion, or ${\text{NO}}_{2}^{-}$, is composed of one nitrogen atom, $\text{N}$, and two oxygen atoms, ${\text{O}}_{2}$, arranged with an imbalance of 1 electron, hence the negative charge.

The nitrite ion will form ionic bonds with a variety of positively charged ions (or cations) due to the electrostatic attraction between the negative and the positive charges.

Compounds formed by ${\text{NO}}_{2}^{-}$ include

Sodium nitrite - $N a N {O}_{2}$ - formed when the $N {a}^{+}$ cation is ionically bonded to the $N {O}_{2}^{-}$ anion;

Magnesium nitrite - $M g {\left(N {O}_{2}\right)}_{2}$ - formed when a $M {g}^{2 +}$ cation if bonded to the nitrite anion;

Barium nitrit - $B a {\left(N {O}_{2}\right)}_{2}$ - formed when a $B {a}^{2 +}$ cation bonds with the nitrite anion;

Potassium nitrite - $K N {O}_{2}$ - formed when a ${K}^{+}$ cation bonds with the nitrite anion.

Here's a link to a list containing more compounds formed by the nitrite polyatomic ion

http://www.endmemo.com/chem/common/nitrite.php

A link to an answer on how polyatomic ions bond posted by other contributors: