#"Bicarbonate anion"# is trigonal planar with respect to the central carbon atom....
Explanation:
You gots #HO-C(=O)-O^(-)#. There are three regions of electron density round the central carbon, and VESPER insists that these adopt a trigonal planar geometry to minimize the interaction of lone electron pairs. Each #/_O-C-O=120^@# to a first approx.