OXIDE OF ANTIMONY. 637 



which combine with the sulphur and disengage the antimony. 

 Or it may be obtained in a state of greater purity, by igniting 

 strongly in a crucible, a quantity of the potash-tartrate of anti- 

 mony, and placing the metallic mass obtained, in water, to re- 

 move any potassium it may have acquired. Antimony is a 

 white and brilliant metal, generally possessing a highly lamel- 

 lated structure. It is easily obtained in rhombohedral crystals 

 of the same form as arsenic and tellurium. Its density is from 

 6. /02 to 6.86. It undergoes no change in the air. The point 

 of fusion of antimony is estimated at 797; it may be distilled 

 at a white heat. This metal burns in air at a red heat, and 

 produces copious fumes of oxide of antimony. Antimony com- 

 bines in three proportions with oxygen, forming oxide of anti- 

 mony and antimonic acid, SbO 3 and SbO 5 , which correspond 

 respectively with arsenious and arsenic acids, and antimonious 

 acid SbO 4 , which is probably an intermediate or compound 

 oxide, analogous to the black oxide of iron . 



Oxide of antimony, Sb O 3 , 1912.9 or 153.28.- Oxide of an- 

 timony may be obtained by dissolving the sulphuret finely 

 pounded, and in the condition in which it is known as prepared 

 sulphuret of antimony, in four times its weight of concentrated 

 hydrochloric acid. Pure sulphuretted hydrogen comes off, and 

 the antimony is converted into terchloride (Sb S 3 and 3H Ci 

 = Sb C1 3 and 3HS.) The clear solution may be poured off, 

 and precipitated at the boiling point by a solution of carbonate 

 of potash, added in excess ; the carbonic acid, which does not 

 combine with oxide of antimony, escapes as gas. Oxide of an- 

 timony so prepared, is anhydrous, but is slightly soluble in 

 water ; it is white, but assumes a yellow tint when heated. It 

 is fusible at a red heat, and sublimes at a high temperature in 

 a close vessel, where it cannot pass into a higher state of oxida- 

 tion. The brilliant crystalline needles which condense about 

 antimony in a state of combustion are likewise this oxide. 

 They possess the unusual prismatic form of arsenious acid ob- 

 served by Wohler. Oxide of antimony also crystallizes as 

 frequently in regular octohedrons, the other form of arsenious 

 acid. It occurs in the prismatic form, as a rare mineral, of 

 which the density is 5.227. 



When a solution of potash is poured upon the bulky hydrate 

 of oxide of antimony, which is precipitated from the chloride 

 by water, a portion of the oxide is dissolved, but the greater 



