Prep. By neutralizing a solution of oxalic acid by means of sesquicarbonate of ammonia, and subsequently evaporating and crystallizing the oxalate of ammonia which is formed.

Prop. & Comp. & Use. Colourless prismatic crystals; without odour; soluble in water. Composition (Nh4 O, C2 O3 + HO). It is introduced into the Pharmacopoeia, to be used in solution as a test for the detection of lime, and its separation from magnesia. It is a poisonous salt.

The solution of the oxalate of ammonia of the Appendix contains half an ounce of salt to 20 ounces of distilled water.