BISMUTH. 597 



happens with suboxide of copper, and appears to indicate that 

 suboxide of bismuth forms salts, at least in the dry way. 



Protoxide of bismuth, BiO ; 986.9 or 79.07 ; BiO. Is ob- 

 tained by the combustion of bismuth, as a straw yellow powder, 

 or by the ignition of the subnitrate. The density of the fused 

 oxide is 8.2 11. It combines with acids, and forms white salts. 



Sulphuret of bismuth., Bi S, occurs crystallized, and has, 

 according to Mr. W. Phillips, a form similar to sulphuret of 

 antimony. Hence M. Regnault is disposed to class bismuth 

 with antimony, (An. de Ch. &c. t. 73, p. 70.) The eq. of bis- 

 muth would then be multiplied by 3, or made 2660.7, and the 

 protoxide be represented by Bi O 3 . Its density is 7-501. The 

 sulphuret is dissolved by the metal in all proportions, by fusion, 

 but separates again when the latter congeals (Lagerhjelm). 



Chloride of bismuth, and sulphate of the oxide of bismuth, are 

 formed, by dissolving oxide of bismuth in concentrated hydro- 

 chloric and sulphuric acids. They both afford subsalts, when 

 decomposed by water, namely BiCl + 2BiO + HO (Phillips,) 

 and 3BiO + SO 3 (Berzelius). The former is known as pearl 

 white. An insoluble subcarbonate of bismuth precipitates, on 

 throwing the nitrate into the solution of an alkaline carbonate, 

 which is used in medicine ; also a crystalline tartrate of bismuth, 

 on adding the nitrate to a solution of Rochelle salt. 



Nitrate of bismuth] BiO, NO 5 + 3HO; 1664 + 337.5 or 133. 

 33+27. This salt is produced when bismuth in powder is 

 thrown into nitric acid, of density 1.42; the action is very 

 violent. Crystals are formed on cooling, which correspond in 

 composition with the magnesian nitrates. This salt is decom- 

 posed by heat in the same way as the nitrate of copper, but at a 

 lower temperature, beginning to lose acid in dry air at 80. 

 Three atoms of the hydrated salt are resolved by heat 

 into 2 atoms of hydrated nitrate of water (acid of sp. gr. 

 1.42), and I atom of subnitrate of bismuth : 3(BiO, NO 5 + 3HO) 

 =2(HO, NO 5 + 3HO), and HO, NO 5 + 3BiO. The neutral 

 nitrate, and all the soluble salts of bismuth are decomposed by 

 water, which combines with the acid and throws down the 

 oxide, generally in combination with a portion of the acid. 

 Oxide of bismuth must, therefore, be considered as inferior to 

 water, in basic power. The nitrate of bismuth is highly corro- 

 sive ; it is precipitated as a black sulphuret by sulphuretted hy- 

 drogen. 



