Answer
See explanation
Work Step by Step
To answer this question, we need to write the Lewis structures and assign formal charges for the cyanate ion (OCN⁻) and the fulminate ion (CNO⁻), and then explain why the fulminate ion is so unstable.
Lewis Structures:
1. Cyanate ion (OCN⁻):
Lewis structure:
O=C=N⁻
Formal charges:
O: 0
C: +1
N: 0
2. Fulminate ion (CNO⁻):
Lewis structure:
C≡N⁻-O
Formal charges:
C: +1
N: 0
O: -1
The fulminate ion (CNO⁻) is very unstable compared to the cyanate ion (OCN⁻) due to the distribution of formal charges and the overall stability of the structure.
In the cyanate ion (OCN⁻), the carbon atom has a formal charge of +1, while the oxygen and nitrogen atoms have formal charges of 0. This distribution of formal charges is more stable because the positive charge is localized on the carbon atom, which is more electronegative than the oxygen and nitrogen atoms.
In the fulminate ion (CNO⁻), the carbon atom has a formal charge of +1, the nitrogen atom has a formal charge of 0, and the oxygen atom has a formal charge of -1. This distribution of formal charges is less stable because the negative charge is localized on the oxygen atom, which is more electronegative than the carbon and nitrogen atoms.
Additionally, the fulminate ion (CNO⁻) has a linear structure, with the carbon atom triple-bonded to the nitrogen atom and the oxygen atom attached to the nitrogen atom. This arrangement of atoms creates a highly strained and unstable structure, which is the primary reason why fulminate salts are so explosive when struck.
In contrast, the cyanate ion (OCN⁻) has a more stable, linear structure with the carbon atom double-bonded to the oxygen atom and the nitrogen atom attached to the carbon atom. This arrangement of atoms is more stable and less prone to explosive behavior.
