Algarot

Algarot, is a white emetic powder formerly used in alchemy that consists of a compound of trichloride and trioxide of antimony. It was used as an emetic because it purges violently both upwards and downwards.

Alternative names
Algarot is also known as mercurius vitæ ("mercury of life"), emetic powder, powder of algaroth, algarel, antimonious oxychloride, or antimony hypochlorite.

Synthesis
Historically, algarot was prepared of butter of antimony (antimony trichloride), which was no more than the regulus of that mineral, dissolved in acids, and separated again by means of several lotions with lukewarm water, which absorbed those acids. By collecting all the lotions and evaporating two third parts, what remained was a very acid liquor, called "Spirit of Philosophical Vitriol".

At present, algarot is synthesised by exposing antimony trichloride to water, like so:
 * SbCl3 + H2O → SbOCl + 2HCl