Which of the following is true about the geometry of the glycinium cation [VISUAL]? — Bonding Chemistry Question

### STEPS:

1. Analyze the geometry around the carbonyl carbon (the rightmost carbon atom): This carbon atom is bonded to three neighboring atoms: the leftmost carbon atom, a double-bonded oxygen atom, and a single-bonded oxygen atom. It has zero nonbonding lone pairs of electrons.
2. Apply VSEPR theory to the carbonyl carbon: Because this carbon has exactly three electron domains (all of which are bonding domains), it exhibits a trigonal planar molecular geometry with $sp^2$ hybridization.
3. Determine coplanarity based on trigonal planar geometry: According to VSEPR theory, all four atoms in a trigonal planar arrangement lie in the same flat plane. Therefore, the carbonyl carbon, the other carbon atom, and both oxygen atoms are coplanar, meaning both $\text{C}$ atoms and both $\text{O}$ atoms lie in the same plane. This makes Option B the correct statement.
4. Evaluate the geometry of other central atoms in the cation:
* Leftmost carbon atom ($\alpha$-carbon): This carbon is single-bonded to four atoms ($\text{N}$, two $\text{H}$'s, and the carbonyl $\text{C}$) with no nonbonding lone pairs. It has four electron domains, meaning the geometry around it is roughly tetrahedral.
* Nitrogen atom: The nitrogen atom is bonded to four atoms (three $\text{H}$'s and the leftmost $\text{C}$) with no nonbonding lone pairs, giving it four electron domains. The geometry of the electron domains around the nitrogen atom is roughly tetrahedral.

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### WHY_OTHERS_WRONG:

• Option A is incorrect: The leftmost carbon atom is bonded to four atoms and has four electron domains, giving it a three-dimensional tetrahedral molecular geometry rather than a planar one. Thus, the atoms bonded to it do not all lie in the same plane.
• Option C is incorrect: Because the leftmost carbon atom has tetrahedral geometry, the $\text{N-C-C}$ bond angle is roughly $109^\circ$, which is significantly bent compared to a linear $180^\circ$ angle.
• Option D is incorrect: The nitrogen atom is bonded to four atoms and has four electron domains, giving it a three-dimensional tetrahedral geometry rather than a planar one.