A poisonous crystalline acid with a sour taste, present in rhubarb leaves, wood sorrel, and other plants.
- ‘It is an excellent source of beta-carotene, vitamins C, E and K, calcium, potassium, iron, sodium, sulphur, folic acid and oxalic acid.’
- ‘Then apply a solution of 4 ounces oxalic acid crystals dissolved in one gallon of warm water.’
- ‘When it does so, however, it leads to the formation of highly toxic products - formic acid and oxalic acid, respectively.’
- ‘Many cleaners are basically bleaches, containing bleaching agents, such as sodium hypochlorite or oxalic acid.’
- ‘Mix the ferric ammonium citrate and oxalic acid well, then add the silver nitrate.’
Late 18th century: oxalic from French oxalique, via Latin from Greek oxalis ‘wood sorrel’.
We take a look at several popular, though confusing, punctuation marks.