Cyanate and thiocyanate ions template

OCN⁻ and SCN⁻: ⁻O–C≡N ↔ O=C=N⁻ and ⁻S–C≡N ↔ S=C=N⁻, two contributors each with the charge on the chalcogen or on nitrogen.

What the template shows

• Linear ions with the negative charge on either end
• Resonance contributors
• Cyanate ion
• OCN⁻: O⁻ form ↔ N⁻ form
• Thiocyanate ion
• SCN⁻: S⁻ form ↔ N⁻ form
• In cyanate the form with O⁻ (the most electronegative atom) is the major contributor; in thiocyanate both forms contribute strongly.
• A third form with the charges ⁺O≡C–N²⁻ is a very minor contributor and is usually left out.
• Both ions are ambident: SCN⁻ binds soft metals through S (thiocyanato) and hard ones through N (isothiocyanato); alkylation gives R–SCN or R–NCS.
• Contributors are not in equilibrium: the real species is one hybrid of them · every part of this figure is editable

Drawn with 12 atoms, 6 arrows, 3 shapes – every one editable in MolDraw.

Sources

• Housecroft & Sharpe, Inorganic Chemistry, 5th ed., Pearson 2018 Textbook