The largest applications for metallic antimony are as alloying material for lead and tin and for lead antimony plates in lead – acid batteries . Alloying lead and tin with antimony improve the properties of the alloys which are used in solders , bullets and plain bearings . Antimony compounds are prominent additives for chlorine and bromine @-@ containing fire retardants found in many commercial and domestic products . An emerging application is the use of antimony in microelectronics .