Kind of bond that's archetypal, caught only once (5)
I believe the answer is:
ionic
'kind of bond' is the definition.
(type of chemical bond)
I can't explain the remainder of the clue.
(Other definitions for ionic that I've seen before include "A type of classical Greek column" , "A classical order of architecture" , "Pertaining to charged particle" , "Greek architectural style" , "ancient order" .)