272 BENZENE. 



Disulphodipheny lie acid, C 12 H 8 (S0 2 .OH) 2 , is form- 

 ed by dissolving diphenyl in concentrated sulphuric 

 acid. Long, colorless prisms, that fuse at 72.5. Very 

 easily soluble in water. The potassium salt, C 12 H 8 .S 2 6 K 2 

 + 2 JH 2 0, crystallizes in large, colorless prisms, moder- 

 ately difficultly soluble in cold water. The barium 

 and lead salts are insoluble in water. 



Diphenylbenzene, C 18 H 14 = C 6 H 4 j ^ Is pro- 

 duced like diphenyl by the action of sodium on a mix- 

 ture of mono- and dibrombenzene. Colorless, crystal- 

 line mass. Fusing point, 205 ; boiling point, 400. 



Mercuryphenyl, (C 6 H 5 ) 2 Hg. Is produced, when, to 

 a solution of monobrombenzene in benzene, sodium- 

 amalgam is added, and the whole then heated for a 

 few hours in connection with an inverted condenser ; 

 the formation takes place particularly easily in the 

 presence of a little acetic ether. (See Mercury ethyl, 

 p. 62). Colorless, rhombic prisms, that become yellow 

 in contact with the air. Fusing point, 120. Insolu- 

 ble in water, easily soluble in chloroform, carbon bisul- 

 phide, and benzene, more difficultly in ether and boil- 

 ing alcohol. "When carefully heated, it can be par- 

 tially sublimed without decomposition ; it is, however, 

 partially resolved into mercury, benzene, diphenyl, and 

 carbon. Treated with two molecules chlorine, bromine, 

 or iodine, it is resolved into monochlor-, brom-, or 

 iodobenzene, and mercury chloride, bromide, or iodide ; 

 treated with only one molecule of the halogenes, or 

 heated with mercury chloride, bromide, or iodide and 

 alcohol at 110, it is converted into mercurymono- 

 phenyl chloride, C 6 H 5 .Hg.Cl (rhombic plates, fusing point, 

 250), bromide, C 6 H 5 .Hg.Br (rhombic plates, fusing 

 point, 275-276), and iodide, C 6 H 5 .Hg.I (rhombic 

 plates, fusing point, 265-266). Hydrogen, sodium, 

 and alkaline sulphides regenerate mercury phenyl from 

 these compounds. "When the chloride is heated with 



