Final answer:
The three main components of gunshot residue are barium, antimony, and lead, which are byproducts of ammunition combustion and can indicate if someone has recently fired a gun.
Step-by-step explanation:
Components of Gunshot Residue
The three main components of gunshot residue (GSR) are barium, antimony, and lead. These elements are byproducts of the combustion of the primer and propellant found in most ammunition. When a gun is fired, these elements vaporize and then condense into fine particles. As these particles cool, they form a residue that can deposit on the hands or clothing of the person firing the gun, as well as on nearby surfaces.
Gunshot residue analysis can be important in forensic investigations to determine if someone has recently fired a weapon. The presence of barium, antimony, and lead together is a strong indicator of gunshot residue, although individual particles containing only one or two of these elements can also be present. Advanced techniques such as scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) are used to identify the characteristic particles in GSR.