ammoniac vs ammoniacal

ammoniac is a noun but ammoniacal is not a noun.

Word	Noun	Adjective	Verb	Adverb
ammoniac	Yes	Yes	No	No
ammoniacal	No	Yes	No	No

As adjectives, ammoniac and ammoniacal are synonyms defined as:

ammoniac and ammoniacal: pertaining to or containing or similar to ammonia

ammoniac (noun)	ammoniacal (noun)
the aromatic gum of the ammoniac plant

ammoniac (adjective)	ammoniacal (adjective)
pertaining to or containing or similar to ammonia	pertaining to or containing or similar to ammonia