The oxide is converted into its hydrated form, and the resulting swelling reduces the porosity of the surface.

The hydrated form has 3 molecules of water per molecule of methylene blue.

The hydrated form is freely soluble in water, ethanol, and acetone.

It has two forms: a dry form and a hydrated form.

The hydrated form is safer to handle.

It is a hydrated form of sodium aluminium sulfate (soda alum).

The anhydrous (without water) form and the hydrated (with water) form can be quite different.

Anhydrous copper sulfate is white or light green, while the hydrated form is blue.

Several hydrated and basic forms of magnesium carbonate also exist as minerals.

The anhydrous form is easily produced from the hydrated form by gentle warming.