Éclaircir belong to the 2nd
group. Éclaircir is a very common french verb.
Éclaircir is conjugated the same way that verbs that end in : -ir
Éclaircir is conjugated with auxiliary avoir
Éclaircir verb is
French verb éclaircir can be conjugated in the reflexive form: S'éclaircir
verb is a direct transitive verb, so passive voice can be used.