Cadet's fuming liquid was the first organometallic compound to be synthesized. In 1760, the French chemist Louis Claude Cadet de Gassicourt

Louis Claude Cadet de Gassicourt

Louis Claude Cadet de Gassicourt was a French chemist who synthesised the first organometalic compound.He obtained a red liquid by the reaction of potassium acetate with arsenic trioxide...

 (1731-1799) synthesized a red liquid by the reaction of potassium acetate

Potassium acetate

Potassium acetate is the potassium salt of acetic acid.-Preparation:It can be prepared by reacting a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic acid:...

 with arsenic trioxide

Arsenic trioxide

Arsenic trioxide is the inorganic compound with the formula As2O3. This commercially important oxide of arsenic is the main precursor to other arsenic compounds, including organoarsenic compounds. Approximately 50,000 tonnes are produced annually...

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4 KCH₃COO + As₂O₃ → As₂(CH₃)₄O + 4 K₂CO₃ + CO₂

The liquid contains a mixture of cacodyl

Cacodyl

Cacodyl, dicacodyl, tetramethyldiarsine, alkarsine or minor part of the "Cadet's fuming liquid" 2As—As2 is a poisonous oily liquid with a garlicky odor...

 and cacodyl oxide

Cacodyl oxide

Cacodyl oxide is a chemical compound of the formula [2As]2O. This organoarsenic compound is primarily of historical significance as it is sometimes considered to be the first organometallic compound synthesized in relatively pure form....

. These were the first organometallic substances prepared, so Cadet can be regarded as the father of organometallic chemistry.