# What is the formula for iron (III) sulfide?

Jul 9, 2016

The molecule formula is $F {e}_{2} {S}_{3}$

#### Explanation:

The molecule iron (III) sulfide is an ionic molecule between the metal Iron and the non-metal sulfur.

In an ionic molecule the formula is determined by balancing the charges on the ions.

For this case the roman numeral (III) tells us the iron has a charge of $+ 3$ or $F {e}^{+ 3}$

The the element sulfur has a charge of $- 2$ or ${S}^{- 2}$

To balance these ion charges it takes two $+ 3$ iron ions to balance three $- 2$ sulfide ions.

The molecule formula is $F {e}_{2} {S}_{3}$