Which group 2 oxide is known for burning brightly in oxygen?

The oxide that is known for burning brightly in oxygen is barium oxide, BaO. Barium, as a group 2 element, has a significant reaction with oxygen, producing a bright flame predominantly due to the high-energy excitation of its atoms when they oxidize. The bright greenish-yellow flame emitted is characteristic when barium compounds are involved, often used in pyrotechnics for producing vivid colors.

In contrast, other group 2 oxides such as magnesium oxide (MgO), calcium oxide (CaO), and beryllium oxide (BeO) do not exhibit this striking combustion characteristic. While they do react with oxygen, they tend to produce less visually impressive combustion effects compared to barium. This distinct behavior of barium oxide under combustion conditions is the reason it stands out among its group.