Calcium oxalate

• Calcium oxalate
• Calciumethandioat

• 563-72-4
• 5794-28-5 (monohydrate)

Colorless cubic crystals (monohydrate)

Fixed

2.12 g · cm -3 ( monohydrate)

200 ° C ( crystalline water)

Practically insoluble in water

Attention

375 mg · kg -1 ( LD50, rat, oral)

-1360.6 KJ / mol

Template: Infobox chemical / molecular formula search available

Calcium is a calcium salt of oxalic acid. It has the molecular formula CaC2O4 and belongs to the group of oxalates.

Occurrence

In nature, calcium oxalate occurs as a major constituent of kidney stones and beer stein. In addition, it comes in many plants as a defense against corrosion ( eg in the sign - sorrel, black bryony, rhubarb, parsnips, and aroids Dieffenbachia in ). In addition to these biological sources of calcium oxalate is found in nature in hydrate as the rare minerals Whewellite and Weddellit.

Production and representation

Calcium is an intermediate in the production of oxalic acid. In this case, sodium oxalate is converted to calcium hydroxide in the hardly soluble calcium oxalate from the oxalic acid is liberated with sulfuric acid.

Chemical Properties

Calcium oxalate is a colorless salt of oxalic acid, which forms rhombic crystals. When heated to about 200 ° C, the compound decomposes to release carbon monoxide and the formation of calcium carbonate.

Use

Calcium serves as evidence for calcium ions. Are you a oxalathaltige solution to be determined calcium-containing solution, falls from the sparingly soluble calcium oxalate. It is also used as a bleaching agent and is used in metal cleaners use. It is also produced as a gloss layer on the surface of natural stone (see luster of natural stones ).