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What substance forms when antimony burns in air?

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A labeled periodic table entry for antimony shows its symbol Sb, atomic number 51, atomic weight 121.76, electron configuration, and name. It is a solid, weakly acidic other metal with a rhombohedral crystal structure at room temperature. — antimony Properties of antimony.

When antimony is heated in air, it burns with a brilliant blue flame and produces white fumes of antimony trioxide (Sb $_{2}$ O $_{3}$ or Sb $_{4}$ O $_{6}$ ). This compound is also known as antimonious oxide and is widely utilized in industrial applications, particularly as a flame retardant in plastics, rubber, textiles, and paints.12