White phosphorous

White phosphorus is a highly reactive and flammable chemical substance composed of phosphorus atoms arranged in a specific structure. It glows faintly in the dark when exposed to oxygen—called phosphorescence—due to its tendency to oxidize and release light. It must be stored under water to prevent it from catching fire spontaneously, as it ignites easily when exposed to air at room temperature. White phosphorus is used in industry for products like matches and in military applications, but it is toxic and must be handled with care to avoid burns and poisoning.