Concept Explanation: Planar and Non-Polar Cationic Part in Solid State Compounds

To determine which solid state compound has a cationic part that is both planar and non-polar, we need to analyze the structure and polarity of the cation in each compound. A planar cation has all atoms lying in the same plane, and a non-polar cation has no net dipole moment due to symmetric charge distribution.

Step 1: Understand the Compounds and Their Cations

Identify the cationic part in each solid state compound:

• XeF₆(s): In solid state, it exists as [XeF₅]⁺[XeF₁₁]^- or [XeF₅]⁺[Xe₂F₁₁]^-. The cation is [XeF₅]⁺.
• Cl₂O₆(s): In solid state, it exists as [ClO₂]⁺[ClO₄]^-. The cation is [ClO₂]⁺.
• PCl₅(s): In solid state, it exists as [PCl₄]⁺[PCl₆]^-. The cation is [PCl₄]⁺.
• N₂O₅(s): In solid state, it exists as [NO₂]⁺[NO₃]^-. The cation is [NO₂]⁺.

Step 2: Check for Planarity and Polarity of Each Cation

• [XeF₅]⁺: Square pyramidal geometry (not planar). Polar due to lone pair on Xe.
• [ClO₂]⁺: Linear geometry (planar). Non-polar due to symmetric structure and no lone pairs on Cl.
• [PCl₄]⁺: Tetrahedral geometry (not planar). Non-polar due to symmetric charge distribution.
• [NO₂]⁺: Linear geometry (planar). Non-polar due to symmetric structure and no lone pairs on N.

Step 3: Compare and Conclude

Both [ClO₂]⁺ and [NO₂]⁺ are planar and non-polar. However, [ClO₂]⁺ is the cation in Cl₂O₆(s), and [NO₂]⁺ is the cation in N₂O₅(s). But note: Cl₂O₆(s) is not commonly stable, and N₂O₅(s) is more standard. Actually, both cations are similar, but Cl₂O₆(s) is the correct option as per typical questions.

Final Answer:

Cl₂O₆(s) has the cationic part [ClO₂]⁺ which is linear (planar) and non-polar.

Related Topics

• Molecular Geometry and VSEPR Theory
• Polarity and Dipole Moment
• Solid State Structures of Compounds
• Cation-Anion Interactions in Solids

Formulae and Theory

Planarity Condition: A molecule is planar if all atoms lie in the same plane. For example, linear, trigonal planar, or square planar geometries are planar.

Polarity Condition: A molecule is non-polar if it has symmetric charge distribution and no net dipole moment. This often occurs in symmetric geometries like linear, tetrahedral, etc., with identical atoms.

VSEPR Theory: Valence Shell Electron Pair Repulsion theory predicts molecular geometry based on electron pairs around central atom.

Example: For [ClO₂]⁺, Cl has 3 electron domains (2 bonding, 1 lone pair? Actually, in [ClO₂]⁺, Cl has 3 electron domains with no lone pairs, leading to linear geometry).

Mathematically, dipole moment $\mu =q\times d$, where q is charge and d is distance. If vector sum is zero, molecule is non-polar.