Reaction of PtF₆ with oxygen (O₂) gas results in the formation of an ionic compound, X⁺Y⁻. Correct statement(s) is(are)

The correct answers are: "Valence d-orbitals of the metal ion in X⁺Y⁻ has 5 electrons" and "PtF₆ acts as an oxidant in this reaction."

Step 1 — Identify the ionic compound X⁺Y⁻

This is a historically significant reaction — it was first performed by Neil Bartlett. When PtF₆ (a powerful oxidizer) reacts with O₂ gas, it oxidizes molecular oxygen to form the dioxygenyl cation:

O_2+{\mathrm{PtF}}_6\to O_2^{+}{\mathrm{PtF}}_6^{-}

So the compound X⁺Y⁻ is O₂⁺PtF₆⁻, where:

• X⁺ = O₂⁺ (dioxygenyl cation)
• Y⁻ = PtF₆⁻

Step 2 — Evaluate Option A: "Bond order of X⁺ is 1.5"

Let us find the bond order of O₂⁺ using Molecular Orbital Theory (MOT). The MO filling for O₂ (16 electrons total) follows:

\sigma 1s^2,{\sigma }^{*}1s^2,\sigma 2s^2,{\sigma }^{*}2s^2,\sigma 2p^2,\pi 2p^4,{\pi }^{*}2p^2

O₂⁺ has one fewer electron (15 electrons total), so one electron is removed from the antibonding {\pi }^{*} orbital:

\mathrm{Bond}\mathrm{Order}=\frac{\mathrm{Bonding\; electrons}-\mathrm{Antibonding\; electrons}}{2}=\frac{10-5}{2}=2.5

The bond order of O₂⁺ is 2.5, not 1.5. ❌ Option A is incorrect.

Step 3 — Evaluate Option B: "Valence d-orbitals of the metal ion in X⁺Y⁻ has 5 electrons"

The metal ion in X⁺Y⁻ = O₂⁺PtF₆⁻ is Pt, present in the anion PtF₆⁻.

Let us find the oxidation state of Pt in PtF₆⁻:

• F is −1 each; there are 6 fluorines, giving −6 total.
• Overall charge on PtF₆⁻ is −1.
• So: Pt + (6 × −1) = −1 → Pt = +5

Now, the ground state electron configuration of Pt (Z = 78) is:

\left[\mathrm{Xe}\right]4f^{14}5d^{9}6s^1

When Pt loses 5 electrons to become Pt⁵⁺, electrons are removed from the outermost shells first (6s then 5d):

{\mathrm{Pt}}^{5+}:\left[\mathrm{Xe}\right]4f^{14}5d^5

The valence d-orbital (5d) of Pt⁵⁺ contains exactly 5 electrons. ✅ Option B is correct.

Step 4 — Evaluate Option C: "PtF₆ acts as an oxidant in this reaction"

Recall the oxidation state changes in the reaction:

• O₂: Oxidation state of O = 0 → In O₂⁺, oxidation state of O = +½. (O₂ is oxidized)
• Pt in PtF₆: Oxidation state of Pt = +6 → In PtF₆⁻, oxidation state of Pt = +5. (Pt is reduced)

Since PtF₆ causes oxidation of O₂ (and is itself reduced), it acts as the oxidizing agent (oxidant). ✅ Option C is correct.

Step 5 — Evaluate Option D: "PtF₆ acts as a fluorinating agent"

A fluorinating agent is a species that transfers fluorine atoms (or F⁻ ions) to another substance. In this reaction, no fluorine is transferred to O₂. The O₂ simply loses an electron to become O₂⁺; the fluorines remain entirely with PtF₆⁻. Therefore, PtF₆ does not act as a fluorinating agent here. ❌ Option D is incorrect.

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