Disodium oxalate

Disodium oxalate is a sodium salt of oxalic acid with the molecular formula Na2C2O4. It can act as a reducing agent, and it may be used as a primary standard for standardizing potassium permanganate (KMnO4) solutions.

In biology experiments, sodium oxalate, like citrates, can also be used to remove calcium ions (Ca2+) from blood plasma. It also prevents blood from clotting. Note that by removing calcium ions from the blood, sodium oxalate can impair brain function, and deposit calcium oxalate in the kidneys.