spatiotemporal vs space-time

spatiotemporal is not a noun while space-time is a noun.

Word	Noun	Adjective	Verb	Adverb
spatiotemporal	No	Yes	No	No
space-time	Yes	No	No	No

spatiotemporal (noun)	space-time (noun)
	the four-dimensional coordinate system (3 dimensions of space and 1 of time) in which physical events are located

spatiotemporal (adjective)	space-time (adjective)
of or relating to space and time together (having both spatial extension and temporal duration)
existing in both space and time; having both spatial extension and temporal duration