Trigonal planar
SeO3-2 stands for Selinite Ion.
SeO3 would be acidic, tending to make selenic acid H2SeO4
The name of the compound SeO3 is selenium trioxide.
Sulfur tetraoxide is a trigonal planar. There is the sulfur in the middle and three oxygen that surrounds it with all of them a double bond linking them to the sulfur.
polar
trigonal planar
Lithium is Li^+ , and selenite is SeO3^2-. It will take 2 Li^+ for each SeO3^2-, so the formula is Li2SeO3
Fe2(SeO3)3
The hybridization of SeO3 is sp3, as selenium has four electron groups around it (three bonding pairs and one lone pair). This results in a tetrahedral arrangement of electron pairs and a sp3 hybridization.
There are two unbonded electrons present in SeO3^2-.
The chemical formula for diselenium dichloride is Se2Cl2.