It is a linear molecule that is primarily of interest for research purposes.

Carbonyl selenide is a colorless gas with an unpleasant odor.

[1] Although the compound is quite stable, its solutions gradually revert to elemental selenium and carbon monoxide.

[2] Carbonyl selenide can be produced by treating selenium with carbon monoxide in the presence of amines.

[3] It is used in organoselenium chemistry as a means of incorporating selenium into organic compounds, e.g. for the preparation of selenocarbamates (O-selenocarbamates R−O−C(=Se)−NR'R" and Se-selenocarbamates, R−Se−C(=O)−NR'R", where R is organyl and R' and R" are any group, typically H or organyl).