ANTIMONY. 217 



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

 bonate : 



2SbCl 3 5Sb 2 3 + 3Na 2 CO 3 == 6Sb 2 O 3 + 6NaCl + 3CO 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 39. Pour the antimonous chloride solution (obtained by Ex- 

 periment 38), 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. 



Analytical reactions. 

 (A solution of antimonous chloride, SbCl 3 , may be used.) 



1. Add hydrogen sulphide to an acidified solution of antimony: 

 an orange-red precipitate of antimonous or autimonic sulphide (Sb 2 S 3 

 or Sb 2 S 5 ) is produced (Plate V., 5). 



2. Add ammonium sulphide to the precipitated sulphide of anti- 

 mony : this is dissolved and may be re-precipitated by neutralizing 

 with an acid. 



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.) 



4. Add sodium hydroxide, ammonium hydroxide, or sodium car- 

 bonate : in either case white antimonous hydroxide Sb(OH 3 ) is pro- 

 duced, which is soluble in sodium hydroxide. 



5. Boil a piece of metallic copper in the solution of antimonous 

 chloride : a black deposit of antimony is formed upon the copper. 

 By heating the latter in a narrow test-tube, the antimony is volatil- 

 ized and deposited as a white incrustation of antimonous oxide upon 

 the glass. 



