
Sodium hydrogenoxalate

Sodium hydrogenoxalate is the sodium salt of hydrogenoxalate. The only difference from oxalic acid is that one of the two hydrogen atoms has been replaced with a sodium atom. Like oxalate, it is toxic for the kidney function if swallowed because of the precipitation of poorly soluble calcium oxalate stones that can obstruct the kidney tubules.
Stability.
Upon being heated, sodium hydrogenoxalate undergoes cation-pairing to become oxalic acid and sodium oxalate, the latter of which decomposes into sodium carbonate and carbon monoxide.