What is "hydrogenoxalate"

Hydrogenoxalate or hydrogen oxalate is an anion with chemical formula HCO or HOC–CO, derived from oxalic acid by the loss of a single proton; or, alternatively, from the oxalate anion CO by addition of a proton.

The name is also used for any salt containing this anion, such as NaHCO, KHCO, or NHHCO. Hydrogenoxalates may also be called (especially in older literature) binoxalates, acid oxalates, or monobasic oxalates.