water of hydration vs water of crystallisation

water of hydration and water of crystallisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
water of hydration	Yes	No	No	No
water of crystallisation	Yes	No	No	No

As nouns, water of hydration and water of crystallisation are synonyms defined as:

water of hydration and water of crystallisation: the water present in hydrated compounds

Other synonyms of water of hydration include water of crystallization.

water of hydration (noun)	water of crystallisation (noun)
the water present in hydrated compounds	the water present in hydrated compounds