is a yellow-orange solid. It is an unstable compound, with a half-life of about two minutes, disproportionating into xenon trioxide| and xenon gas. Its structure and identity was confirmed by cooling it to −150 °C so that Raman spectroscopy could be performed before it decomposed.
At -78 °C, the majority of XeO decomposed over a period of 72 hours, which was identified by the fading of the original yellow product to a pale yellow. Almost all yellow color indicating pure XeO disappeared over the span of 1 week.
:3 XeO → Xe + 2 XeO