---
title: "Three possible resonance structures for the thiocyanate ion, \\(\\text{SCN}^-\\), are shown in the diagram below.  Based on formal charge principles and relative electronegativities, which of the following identifies the most stable Lewis structure for \\(\\text{SCN}^-\\) and provides the correct justification?"
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url: "https://nerd-notes.com/ubq/119973/"
date_modified: "2026-08-21T08:31:20+00:00"
---

# Three possible resonance structures for the thiocyanate ion, \(\text{SCN}^-\), are shown in the diagram below.

Based on formal charge principles and relative electronegativities, which of the following identifies the most stable Lewis structure for \(\text{SCN}^-\) and provides the correct justification?

Three possible resonance structures for the thiocyanate ion, \(\text{SCN}^-\), are shown in the diagram below.

Based on formal charge principles and relative electronegativities, which of the following identifies the most stable Lewis structure for \(\text{SCN}^-\) and provides the correct justification?

![Three Lewis structures are arranged horizontally from left to right, labeled 'Structure 1', 'Structure 2', and 'Structure 3'. Left (Structure 1): The label 'Structure 1' is above the structure. A sulfur atom symbol S is on the left, single-bonded with one horizontal line to a central carbon atom symbol C, which is triple-bonded with three parallel horizontal lines to a nitrogen atom symbol N on the right. The S atom has exactly three lone pairs of electrons (two dots above, two dots to the left, two dots below). The C atom has zero lone pairs. The N atom has exactly one lone pair (two dots to the right). The structure is enclosed in square brackets with a superscript negative sign '-' at the top right. Middle (Structure 2): The label 'Structure 2' is above the structure. An S atom is on the left, double-bonded with two parallel horizontal lines to a central C atom, which is double-bonded with two parallel horizontal lines to an N atom on the right. The S atom has exactly two lone pairs (two dots above, two dots below). The C atom has zero lone pairs. The N atom has exactly two lone pairs (two dots above, two dots below). The structure is enclosed in square brackets with a superscript negative sign '-' at the top right. Right (Structure 3): The label 'Structure 3' is above the structure. An S atom is on the left, triple-bonded with three parallel horizontal lines to a central C atom, which is single-bonded with one horizontal line to an N atom on the right. The S atom has exactly one lone pair (two dots to the left). The C atom has zero lone pairs. The N atom has exactly three lone pairs (two dots above, two dots to the right, two dots below). The structure is enclosed in square brackets with a superscript negative sign '-' at the top right. All elements and lines are rendered in grayscale on a white background. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787301080-tcmZuc.jpg)

- **A.** Structure 1, because it places the \(-1\) formal charge on sulfur, which has a larger atomic radius than nitrogen.
- **B.** Structure 1, because the carbon-nitrogen triple bond provides greater bond energy than two double bonds.
- **C.** Structure 2, because the formal charges are minimized and the \(-1\) formal charge is on the more electronegative nitrogen atom.
- **D.** Structure 3, because nitrogen is more electronegative than sulfur and thus stabilizes a \(-2\) formal charge.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119973/*