175 



SODIUM. NA. 



78. METALLIC. 



o. In pellets, preserved from oxidation in Persian naphtha. 

 b. Fused, in a hermetically sealed glass tube. 



79. ACETATE. Na C 9 H 3 8 , 3H 2 0. 



a. Impure, in large crystals. 



b. Pure, in crystals. 



c. Pure, in acicnlar crystals. 



Note. Specimen c closely resembles the sulphates of zinc and mag- 

 nesium in appearance. For peculiarities in the crystallization of this 

 salt, see Gerhardt, Chemistry, vol. i., p. 11. 



80. ANTIMONIATE. Na, H 2 Sb a 7 , 6H 2 0. (Metantimoniate of 



Sodium.) 

 a. Powder. 



81. ARSENATB. Na 2 H As 0^, 12H 2 0. (Arsenate of Sodium, Disodic 



Ar senate.) 



a. Crude. 



b. Pure, in crystals. (Sodce Arsenias, B. P.) 



c. Ditto, dried at 300 F. 



Note. This salt also crystallizes with seven molecules of water of 

 liydration. When effloresced it also retains seven equivalents of water. 

 See Attfteld, Chemistry, p. 181 ; Fownes, Chemistry, p. 483. Specimen c 

 is the form in which the salt is directed to be used in the British Phar- 

 macopoeia in order to secure uniformity of strength in the liquor sodas 

 arsenitis. 



82. BIBORATE. NagB^Oy, 10H 2 ; possibly a double Metaborate, 



2Na B Os, 2H B 2 , 9H 3 0. 



a. Native. (Tincal.) 



b. Pure, in crystals. (Prismatic Borax.) 



c. Pure, in crystals. (Octahedral Borax.) 



Note. Specimen c contains less water of crystallization than specimen 

 b, and is crystallized in a different form. See Watts, Diet. Chem., vol. i., 

 p. 647. For fig. of crystal, see Royle, Mat. Med.j p. 158. 



83. CARBONATE. Na 2 C 3 , 10H 2 0. (Soda, Washing Soda, Salt of 



Soda.) 



a. Impure. (Barilla; Scotch Soda.) 



Note. Barilla is the ash left after the incineration of Salsola soda and 

 other maritime plants. 



The following specimens illustrate the manufacture of CAR- 

 BONATE OF SODIUM from common salt. See Fownet, 

 Chemistry, p. 333. 



a. Black ash. 



b. Residuum after lixiviating black ash. 



