---
title: "The thiocyanate ion, \\(\\text{SCN}^-\\), is a polyatomic anion consisting of sulfur, carbon, and nitrogen arranged with carbon as the central atom. Three valid resonance structures that satisfy the octet rule for all atoms are shown below.  Based on formal charge principles and relative electronegativities, which structure represents the most favorable contributor to the resonance hybrid of \\(\\text{SCN}^-\\), and why?"
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url: "https://nerd-notes.com/ubq/121512/"
date_modified: "2026-08-23T05:04:57+00:00"
---

# The thiocyanate ion, \(\text{SCN}^-\), is a polyatomic anion consisting of sulfur, carbon, and nitrogen arranged with carbon as the central atom. Three valid resonance structures that satisfy the octet rule for all atoms are shown below.

Based on formal charge principles and relative electronegativities, which structure represents the most favorable contributor to the resonance hybrid of \(\text{SCN}^-\), and why?

The thiocyanate ion, \(\text{SCN}^-\), is a polyatomic anion consisting of sulfur, carbon, and nitrogen arranged with carbon as the central atom. Three valid resonance structures that satisfy the octet rule for all atoms are shown below.

Based on formal charge principles and relative electronegativities, which structure represents the most favorable contributor to the resonance hybrid of \(\text{SCN}^-\), and why?

![A horizontal diagram displaying three candidate Lewis structures for \(\text{SCN}^-\), labeled Structure 1, Structure 2, and Structure 3 from left to right. Each structure is enclosed in square brackets with an overall negative charge superscript outside the right bracket. Structure 1 shows \(\text{S}\) with three lone pairs singly bonded to central \(\text{C}\), which is triply bonded to \(\text{N}\) with one lone pair; \(\text{C}\) has zero lone pairs. Structure 2 shows \(\text{S}\) with two lone pairs doubly bonded to central \(\text{C}\), which is doubly bonded to \(\text{N}\) with two lone pairs; \(\text{C}\) has zero lone pairs. Structure 3 shows \(\text{S}\) with one lone pair triply bonded to central \(\text{C}\), which is singly bonded to \(\text{N}\) with three lone pairs; \(\text{C}\) has zero lone pairs. Every structure contains exactly \(16\) valence electrons. No formal charges, color, or other annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787461497-DgnI4b.jpg)

- **A.** Structure 1, because the presence of a carbon-nitrogen triple bond provides a higher bond enthalpy than two double bonds.
- **B.** Structure 1, because the negative formal charge is placed on the sulfur atom, which has a larger atomic radius and greater polarizability than nitrogen.
- **C.** Structure 3, because it distributes non-zero formal charges across all peripheral atoms to maximize electrostatic stabilization.
- **D.** Structure 2, because the formal charges on all atoms are minimized and the negative formal charge resides on the more electronegative nitrogen atom.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121512/*