# What are an ionic formulas?

Jul 16, 2018

Ionic formulas are ions that are held together by electrostatic attraction.

#### Explanation:

Given: What are ionic formulas?

Ionic crystals have ionic formulas. They are held together by electrostatic attraction .

There is a positive ion known as a cation attracted to a negative ion called an anion. The positive or negative ion can be polyatomic (an ion that is a group of ions that together have a positive or negative charge).

Ionic formulas are not a molecular formula, they are what is called a formula unit, a ratio of ions.

Examples:

$\underline{\text{ Name formula unit ions }}$
sodium chloride: $\text{ NaCl (salt) "Na^+ " } C {l}^{-}$
calcium chloride: $\text{ "CaCl_2 " "Ca^(+2) " } C {l}^{-}$
barium oxide: $\text{ "BaO " "Ba^(+2) " } {O}^{- 2}$
iron (III) bromide: $\text{ "FeBr_3" "Fe^(+3) " } B {r}^{-}$
ammonium sulfide:$\text{ "(NH_4)_2S" "NH_4^+" } {S}^{-} 2$
ammonium carbonite:${\left(N {H}_{4}\right)}_{2} C {O}_{2} \text{ " NH_4^+" } C {O}_{2}^{-} 2$

Jul 16, 2018

Ionic formulae represent ionic compounds....i.e. they represent a definite chemical entity, a salt.

#### Explanation:

And ionic compounds are collections of ANIONS and CATIONS such that the resultant charge of the collection, the compound or salt, is ZERO... And so we could take a metal ion, say ${M}^{2 +}$, and marry it up to a collection of anions....i.e. ${X}^{-}$, $C {O}_{3}^{2 -}$, $N {O}_{3}^{-}$, $C l {O}_{4}^{-}$, $H P {O}_{4}^{2 -}$...to give ionic salts WHICH ARE NEUTRAL...i.e. $M {X}_{2}$, $M C {O}_{3}$, $M {\left(N {O}_{3}\right)}_{2}$, $M {\left(C l {O}_{4}\right)}_{2}$, $M H P {O}_{4}$...