What is white phosphorus munitions ? claimed by west that Russia may use them in Ukraine

The phosphorous munition illustration basing on data

White phosphorus munitions are weapons that use one of the common allotropes of the chemical element phosphorus. White phosphorus is used in smoke, illumination, and incendiary munitions, and is commonly the burning element of tracer ammunition.

Though this is just the assumption from the experts ,some politicians and fierce critics of Putin are alleging the weapon might have already been deployed and use in marupoli in the recent week But no one has come out clearly to point finger at Russia about the use of such weapon ,However there are growing sentiment that Russia may desperately use the weapon of this mass destruction if they feel pinned at the wall in certain point .\