ANTIMONY. 361 



It is completely converted into oxide by treating it with sodium car- 

 bonate : 



2SbOCl + Na 2 CO 3 = Sb,O 3 -f 2NaCl + CO 2 . 



The precipitate when washed and dried is a heavy, grayish-white, 

 tasteless powder, insoluble in water, soluble in hydrochloric acid, and 

 also in a warm solution of tartaric acid. Antimonous oxide, while 

 yet moist, dissolves readily in potassium acid tartrate, forming the 

 double tartrate of potassium and antimony, or tartar emetic, which salt 

 will be more fully considered hereafter. 



Experiment 50. Pour the antimonous chloride solution (obtained by Ex- 

 periment 49), which should have been boiled sufficiently to expel all hydrogen 

 sulphide, into 100 c.c. of water, wash by decantation the white precipitate of 

 oxychloride thus obtained, and add to it an aqueous solution of about 1 gramme 

 of sodium carbonate. After effervescence ceases, collect the precipitate on a 

 filter, wash well and treat some of the precipitate, while yet moist, with a solu- 

 tion of potassium acid tartrate, which dissolves it readily, forming tartar emetic. 

 (For the latter compound see index.) 



Antidotes. Poisonous doses of any preparation of antimony are generally 

 quickly followed by vomiting : if this, however, have not occurred, the stomach- 

 pump must be applied. Tannic acid in any form, or recently precipitated ferric 

 hydroxide, should be administered. 



Tests for antimony. 



(Use a solution of antimony chloride prepared as in Experiment 49, and diluted to 

 about 30 c.c. by adding, first, 2 or 3 c.c. of dilute hydrochloric acid, and then water 

 cautiously. Also a 5 percent, solution of tartar emetic, K(SbO)C 4 H 4 O 6 , in water. 

 Note that the latter dissolves easily and without decomposition.) 



1. Add hydrogen sulphide to some of the solution of antimony 

 chloride : an orange-red precipitate of antimonons sulphide (Sb 2 S 3 ) is 

 produced (Plate V., 5). 



Hydrogen sulphide produces the same precipitate in the solution of 

 tartar emetic. 



2. Add yellow ammonium sulphide to the precipitated sulphide of 

 antimony : this is dissolved and may be reprecipitated by neutralizing 

 with an acid. The same results are obtained with caustic alkalies. 



3. Produce a concentrated solution of antimonous chloride by 

 evaporation or by dissolving the sulphide in hydrochloric acid, and 

 pour it into water : a white precipitate of oxychloride is formed. (See 

 explanation above.) 



Add a few drops of dilute hydrochloric acid to some of the solution 

 of tartar emetic : a white precipitate of oxychloride is also formed. In 

 analysis, this might be mistaken for a chloride of silver, lead, or mer- 

 cury, but it differs from the latter by being soluble in excess of the acid. 



