(i) BH4– Boron-hydride ion (BH4–) is formed by the sp3 hybridisation of boron orbitals. Therefore, it is a tetrahedral structure.
(ii) BF3 -- As a result of its small size and high electronegativity, boron tends to form monomeric covalent halides. These halides have a planar triangular geometry. This triangular shape is formed by the overlap of three sp2 hybridized orbitals of boron with the sp orbitals of 3 halogen atoms. Boron is sp2 hybridized in BF3.