Find the word definition

Wiktionary
antimony trichloride

n. (context inorganic compound English) A soft, colourless solid, SbCl3, that has some use as an analytical reagent

Wikipedia
Antimony trichloride

Antimony trichloride is the chemical compound with the formula SbCl. The soft colorless solid with a pungent odor was known to the alchemists as butter of antimony.