Read Xenon Fluoride Hydrolysis Products Before Guessing
Every xenon fluoride hydrolysis question comes down to memorising three specific reactions — XeF2, XeF4 and XeF6 each hydrolyse to a different, specific set of products, none of which is simply 'xenon plus HF.'
Xenon Fluoride Structure and Hydrolysis is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
The three xenon fluoride hydrolysis reactions
XeF2 hydrolyses to give Xe (elemental xenon) + HF + O2 — xenon is REDUCED back to element 0 here. XeF4 disproportionates on hydrolysis to give Xe + XeO3 (some Xe reduced to element, some oxidised up to +6) + HF. XeF6 hydrolyses completely to XeO3 (no elemental Xe produced) + HF — XeF6 is the odd one out, since it does NOT release any elemental xenon on complete hydrolysis, unlike XeF2 and XeF4 which both do.
Partial hydrolysis of XeF6 gives oxyfluorides
Controlled (partial) hydrolysis of XeF6 gives XeOF4 and XeO2F2 as intermediates before complete hydrolysis reaches XeO3 — these oxyfluorides are real, isolable compounds, not just theoretical intermediates, which is why 'which oxyfluoride forms during XeF6 hydrolysis' questions have specific correct answers (XeOF4, XeO2F2) rather than an open-ended list.
VSEPR shapes of xenon oxides and oxyfluorides
XeO3 is pyramidal (3 bonding domains + 1 lone pair on Xe); XeO2F2 is see-saw (5 domains: 2 O + 2 F + 1 lone pair). Structures for Xe compounds follow the exact same VSEPR domain-counting logic used for XeF2/XeF4/XeF6 themselves — count bonding and lone pair domains on Xe first, regardless of whether the ligands are F or O.
OlympIQ exam lens
- ✓XeF2 → Xe + HF + O2 (reduction to elemental Xe).
- ✓XeF4 → Xe + XeO3 + HF (disproportionation — some Xe reduced, some oxidised).
- ✓XeF6 → XeO3 + HF only — no elemental Xe forms, unlike XeF2 and XeF4.
- ✓Partial (controlled) hydrolysis of XeF6 gives real, isolable oxyfluorides XeOF4 and XeO2F2 before reaching XeO3.
Don't assume all three xenon fluorides release elemental Xe on hydrolysis — XeF6 is the exception, hydrolysing completely to XeO3 with no elemental xenon produced, unlike XeF2 and XeF4.
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