Carbon ring coil associated with a petal formation (7)
I believe the answer is:
corolla
'petal formation' is the definition.
(formation of several petals on a flower)
'carbon ring coil associated with a' is the wordplay.
'carbon' becomes 'c' (C is the chemical symbol for carbon).
'ring' becomes 'o' (letter resembling a ring).
'coil' becomes 'roll' (synonyms).
'associated with' is a charade indicator (letters next to each other).
'c'+'o'+'roll'+'a'='COROLLA'
(Other definitions for corolla that I've seen before include "Whorl of flower petals" , "Part of a flower" , "Flower's petals collectively" , "part of plant" , "Internal whorl of a flower" .)