Caesium oxalate

Caesium oxalate (standard IUPAC spelling), or dicesium oxalate, or cesium oxalate (American spelling) is a chemical compound with the chemical formulaCs₂C₂O₄. It is a caesium salt of oxalic acid. It consists of caesium cationsCs⁺ and oxalate anionsC₂O2−4.

Caesium oxalate can be prepared by passing carbon monoxide and carbon dioxide over caesium carbonate at 380 °C:

Cs₂CO₃ + CO → Cs₂C₂O₄

Other alkali carbonates do not undergo transformation to oxalate.

Caesium carbonate can react with oxalic acid in aqueous solution to give caesium oxalate.

Cs₂CO₃ + H₂C₂O₄·2H₂O → Cs₂C₂O₄·H₂O + CO₂ + 2 H₂O

Caesium oxalate can be reduced back into caesium carbonate and carbon monoxide by thermal decomposition.

Cs₂C₂O₄ → Cs₂CO₃ + CO

Compounds that contain caesium and another element in addition to the oxalate anion are double salts of caesium and oxalate. The oxalate may form a complex with a metal that can make a salt with caesium.

Examples include:

Mixed anion compounds containing caesium, oxalate and another anion also exist, such as the uranyl sulfate above, and caesium bis(oxalato)borate (CsBOB) (Cs[B(C₂O₄)₂]).