GROUNDS FOR NULLITY OF MARRIAGE
The validity of Church marriage rests on three elements, namely, legal capacity, consent and canonical form. A defect in any of these renders canonical marriage null and void ab initio.
Legal Capacity means freedom from any and all matrimonial diriment impediments. Diriment impediments render a person incapable of validly contracting marriage.
Consent is the act of the will, by which a man and a woman, with an irrevocable covenant give and accept each other mutually, in order to bring into existence a marriage (can. 1057 §2).
Canonical form refers to the complex of formalities or external solemnities prescribed by law to be followed in order that marriage might be entered into legitimately & validly.