Within the highly complex, butterfly-like spatial geometry of a completely isolated dichromate ion ( — d and f Block Elements Chemistry Question
Question
Within the highly complex, butterfly-like spatial geometry of a completely isolated dichromate ion ($Cr_2O_7^{2-}$), exactly how many distinct $Cr-O$ bonds are structurally defined as non-bridging, strictly equivalent terminal bonds?
💡 Solution & Explanation
The dichromate ion consists of two tetrahedral $CrO_4$ units sharing exactly one bridging oxygen atom. This creates two central, elongated $Cr-O$ bridging bonds. The remaining oxygen atoms reside on the periphery; each chromium atom is bonded to three of these terminal oxygen atoms. Due to rapid internal resonance, all $3 + 3 = 6$ of these terminal $Cr-O$ bonds are strictly identical in length and bond order.