Cacodyl
Cacodyl, dicacodyl, tetramethyldiarsine, alkarsine or minor part of the "
Cadet's fuming liquid" (after the French chemist Louis Claude Cadet de Gassicourt) (CH3)2As—As(CH3)2 is a poisonous oily liquid with a garlicky odor. Cacodyl undergoes spontaneous combustion in dry air.
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Alkarsin
(n.)
A spontaneously inflammable liquid, having a repulsive odor, and consisting of cacodyl and its oxidation products; -- called also Cadel's fuming liquid.
Webster's Revised Unabridged Dictionary (1913), edited by Noah Porter.
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