extinction angle vs angle of extinction

extinction angle and angle of extinction both are nouns.

Word	Noun	Adjective	Verb	Adverb
extinction angle	Yes	No	No	No
angle of extinction	Yes	No	No	No

As nouns, extinction angle and angle of extinction are synonyms defined as:

extinction angle and angle of extinction: the angle from its axis that a crystal must be rotated before appearing maximally dark when viewed in polarized light

extinction angle (noun)	angle of extinction (noun)
the angle from its axis that a crystal must be rotated before appearing maximally dark when viewed in polarized light	the angle from its axis that a crystal must be rotated before appearing maximally dark when viewed in polarized light