Note upon sodium antimonyl tartrate

Sodium antimonyl tartrate was described in 1842 by Dumas and Prira, who gave it the constitution C8 H8 O10 NaO,Sb2 O3 H2 O, but did not state how they had prepared it Clarke and Evans obtained a compound of the composition 3Na2 C4 H4 O6 + 2Sb(OH)3 + 3H2 O, in 1883, by saturating tartaric acid with antimony trioxide and neutralising the solution with sodium carbonate. The first compound does not seem to have prepared again since 1842. Sodium antimonyl tartrate was prepared according to the methods usually given for preparing tartar emetic, by boiling a solution of acid sodium tartrate (13 grammes ) with a little more than the calculated quantity (10 grammes) of antimony trioxide until the latter had almost completely passed into solution. On filtering and concentrating the solution to a small volume no crystallisation occurred, but on adding a little alcohol the whole became solid. This was them dissolved in about twice its volume of hot water, and alcohol was added until precipitation commenced, when, on cooling, the sodium antimonyl tartrate crystallised out. This compound at the ordinary temperature dries very slowly and has a moist appearance, but when driedin vacuo over sulphuric acid it becomes anhydrous and loses 2½ molecules of water of crystallisation, resembling sodium tartrarsenite in this respect. The substance is very easily soluble in water and its solution reacts faintly acid to litmus.