reciprocal vs reciprocative

reciprocal is a noun but reciprocative is not a noun.

Word	Noun	Adjective	Verb	Adverb
reciprocal	Yes	Yes	No	No
reciprocative	No	Yes	No	No

reciprocal (noun)	reciprocative (noun)
hybridization involving a pair of crosses that reverse the sexes associated with each genotype
(mathematics) one of a pair of numbers whose product is 1: the reciprocal of 2/3 is 3/2; the multiplicative inverse of 7 is 1/7
something (a term or expression or concept) that has an inverse relation to something else

reciprocal (adjective)	reciprocative (adjective)
concerning each of two or more persons or things; especially given or done in return	moving alternately backward and forward
of or relating to the multiplicative inverse of a quantity or function	given or done or owed to each other