The manganate and permanganate ions are tetrahedral, due to :
(1) The π-bonding involves overlap of p-orbitals of oxygen with d-orbitals of manganese
(2) There is no π-bonding
(3) The π-bonding involves overlap of p-orbitals of oxygen with p-orbitals of manganese
(4) The π-bonding involves overlap of d-orbitals of oxygen with d-orbitals of manganese