Upon completely isolating exactly one molecular unit of the highly stable, deeply coloured chromate — d and f Block Elements Chemistry Question

💡 Solution & Explanation

The chromate ion ($CrO_4^{2-}$) possesses a tetrahedral geometry characterized by $d^3s$ hybridization on the central $Cr^{6+}$ atom. Structurally, it forms 4 basic sigma ($\sigma$) bonds with the four oxygen atoms. To stabilize the high charge density, two of the oxygen atoms additionally form pi ($\pi$) bonds ($p\pi-d\pi$) with the empty $d$ -orbitals of the chromium. Thus, there are $4\sigma + 2\pi = 6$ total covalent bonds.