Naming Hydrates

Naming Hydrates tutorial

Naming a Hydrate
Hydrates are compounds that attract and bond with water molecules when they crystallize. The two parts of a hydrate are the anhydrous salt and the water of hydration. The ratio of these water molecules in the compound is always a whole number. A sample hydrate formula is written as follows: CuSO4•5H2O. CuSO4 is the anhydrous salt and 5H2O is the water of hydration.

Example: Name CuSO4•5H2O

Description of Action	Action
1. Name the salt.	CuSO4 is copper(II) sulfate
2. Determine the prefix to be used based on the number of water molecules. The list of prefixes used in naming hydrates are listed in a chart below.	There are 5 water molecules, so you should use the prefix penta-. copper(II) sulfate penta-
3. Add the word "hydrate" to the end of the prefix.	copper(II) sulfate pentahydrate

The prefixes used for naming hydrates are as follows:

Prefix	Moles of Water	Name	Formula
mono-	1	monohydrate	XY•H2O
di-	2	dihydrate	XY•2H2O
tri-	3	trihydrate	XY•3H2O
tetra-	4	tetrahydrate	XY•4H2O
penta-	5	pentahydrate	XY•5H2O
hexa-	6	hexahydrate	XY•6H2O
hepta-	7	heptahydrate	XY•7H2O
octa-	8	octahydrate	XY•8H2O
nona-	9	nonahydrate	XY•9H2O
deca-	10	decahydrate	XY•10H2O