ACETATES AND THEIR MANUFACTURE. 297 



any of the preceding salts with lead oxide. It is a white powder 

 slightly soluble in boiling water, from which it crystallizes out in 

 silky needles which consist of 2 equivalents of the salt combined 

 with three equivalents of water. 



Uranium acetate. With uranous oxide acetic acid combines 

 to a dark green crystallizable salt, and with uranic oxide to a 

 yellow basic salt, which, combined with water, appears in two 

 different forms of crystals. It is remarkable for giving, with 

 many other acetates, well crystallizing salts, of a beautiful color 

 and partly showing magnificent dichroism (Wertheim and 

 Weselsky). 



Tin acetate is prepared by dissolving stannous hydrate* in 

 heated strong acetic acid, or by mixing stannous chloride (SnCl 2 ) 

 with acetate of sodium or calcium. It forms small colorless 

 needles which have a strong metallic taste and readily decompose 

 in the air. The salt is sometimes used as a mordant in calico 

 printing. 



Bismuth acetate. Bismuth nitrate prepared by gradually in- 

 troducing pulverized metallic bismuth into cold dilute nitric acid 

 is mixed with pure concentrated sugar of lead solution. The 

 salt separates in small, colorless needles. 



Mercurous acetate can be prepared by dissolving pure mercu- 

 rous oxide or its carbonate in acetic acid, or by mingling hot solu- 

 tions of mercurous nitrate and acetate of sodium or of potas- 

 sium. The pure mercurons carbonate is heated to boiling with 8 

 parts of water, and concentrated acetic acid added until all is dis- 

 solved ; the hot, filtered liquid free from oxide being allowed to 

 cool. Or, acidulated nitrate is diluted with 6 to 8 parts of water, 

 heated and mixed with one equivalent of acetate of sodium or 

 potassium, dissolved in 8 parts of hot water containing a little 

 free acid and cooled. The salt, when separated, is washed with 

 a little cold water, dried in the dark at a gentle heat, and kept 

 from the light in covered bottles. 



It crystallizes in fine, white, silvery scales, flexible and unctuous 

 to the touch, with a nauseous metallic taste, easily decomposed by 



* The hydrate is obtained by precipitating stannous chloride with soda lye 

 and washing the precipitate. 



