A Lewis dot structure for SeO3 is drawn with an Se in the center, with two lines connecting it to two Os and one double line connecting it to an O. The Os connected by single lines are both surrounded by six dots, while the other O has four dots.
In the Lewis dot structure, the Se represents the element selenium, and each O represents oxygen. Each single line indicates a single pair of bonded electrons, while the double line represents two pairs of bonded electrons. The single dots represent one valence electron each.
SeO3 is the chemical formula for the compound selenium trioxide. Different Lewis structures of the same compound are known as resonance structures.