LEAD COPPER-BISMUTH. 191 



color: sulphate, nitrate, chloride, and the ammonio-copper com- 

 pounds are soluble, most other compounds are insoluble. 



Bismuth, Bi m = 2O8.9. Found in nature chiefly in the metallic 

 state, disseminated, in veins, through various rocks. The extraction 

 of the metal is a mere mechanical process, the earthy matter contain- 

 ing it being heated in iron cylinders, and the melted bismuth collected 

 in suitable receivers. 



Bismuth is grayish-white, with a pinkish tinge, very brittle, gen- 

 erally showing a distinct crystalline structure. Occasionally it is 

 used in alloys and in the manufacture of a few medicinal prepara- 

 tions. 



Bismuth is trivalent, as shown in the chloride, BiCl 3 , or oxide, 

 Bi 2 O 3 . A characteristic property of this metal is decomposition of 

 the concentrated solution of any of its normal salts by the addition 

 of much water, with the formation and precipitation of so-called 

 oxysalts or subsalts of bismuth, while some bismuth with a large 

 quantity of acid remains in solution. 



The true constitution of these subsalts is as yet doubtful, but a 

 comparison of them has led to the assumption of a radical Bismuihyl, 

 BiO, which behaves like an atom of a univalent metal. 



The relation between the normal or bismuth salts, and the subsalts 

 or bismuthyl salts, will be shown by the composition of the following 

 compounds : 



Bismuth chloride, BiCl 3 . Bismuthyl chloride, (BiO)Cl. 



" bromide, BiBr 3 . " bromide, (BiO)Br. 



" iodide, BiI 3 . ' iodide, (BiO)I. 



nitrate, Bi(NO 3 ) 3 . nitrate, (BiO)NO 3 . 



" sulphate, Bi 2 (SO 4 ) 3 . " sulphate, (BiO) 2 SO 4 . 



carbonate, Bi 2 (CO 3 ) 3 1 carbonate, (BiO) 2 CO 3 . 



not known. ) 



Bismuthyl nitrate, Bismuth subnitrate, Bismuth! subnitras, 

 BiONO 3 .H 2 O? (Oxynitrate of bismuth). By dissolving metallic bis- 

 muth in nitric acid, a solution of bismuth nitrate is obtained, nitrogen 

 dioxide escaping : 



Bi + 4HNO 3 = Bi(NO 3 ) 3 + NO + 2H 2 O. 



Upon evaporation of the solution, colorless crystals of bismuth 

 nitrate, Bi(NO 3 ) 3 5H 2 O, are obtained. 



If, however, the solution (or the dissolved crystals) be poured into 

 a large quantity of water, the salt is decomposed with the formation 



