406 ANTHRAQUINONE. 



Monpchloranthracene, C 14 IPC1. Is obtained di- 

 rectly from anthracene in a current of chlorine gas; 

 and by decomposing the dichloride with alcoholic 

 potassa. Small, harid, scaly crystals. Dichloranthra- 

 cene, C 14 H 8 C1 2 . Yellow laminae or needles ; fusing point, 

 205; sublimable. Tetrachloranthracene^ u WG\\ Stel- 

 late, gold-colored needles ; fusing point, 220. 



Dibromanthracene, C 14 H 8 Br 2 , is formed alone 

 when bromine is added to a solution of anthracene in 

 carbon bisulphide. Gold-colored needles ; fusing point, 

 221. Heated with alcoholic ammonia at 160-170, it 

 is reconverted into anthracene. Dibromanthracene 

 tetrabromide, C 14 H 8 Br 2 .Br 4 , is formed when bromine 

 vapor is allowed to act on finely divided anthracene 

 or dibromanthracene. Hard, thick, colorless plates ; 

 fuses at 170-180, undergoing decomposition. Tri- 

 bromanthracene, C^HHBr 3 , by heating the preceding 

 compound to 200. Yellow needles; fusing point, 

 169 ; sublimable. Tetrabromanthracene, C 14 H 6 Br 4 . 

 From dibromanthracene tetrabromide with alcoholic 

 potassa. Yellow crystals ; fusing point, 254. 



Nitroanthracene, C 14 H 9 (M) 2 ). Is obtained by heat- 

 ing an alcoholic solution of anthracene with nitric 

 acid. Stellate, red needles. Insoluble in cold alcohol 

 and benzene, difficultly soluble in the hot liquids. 

 Sublimable. 



Anthraquinone (Oxanthracene). 



G14H8 )o>. 



.Formation and preparation. By the oxidation of 

 anthracene, dichlor-, or dibromanthracene with nitric 

 or chromic acid. Can be most readily prepared by 

 adding a solution of chromic acid in glacial acetic 

 acid, or finely powdered potassium bichromate, to a hot 

 solution of anthracene in glacial acetic acid. 



Properties. Purified by sublimation, it forms lus- 

 trous, yellow needles; fusing point, 273 ; insoluble in 



