CHRYSENE. 411 



C 16 H 8 2 , a brick-red powder, which, when heated sub- 

 limes partially in red needles and decomposes partially. 



Chrysene, C 18 II 12 . That portion of the high-boil- 

 ing hydrocarbons of coal-tar (see Pyrene), which is in- 

 soluble in carbon bisulphide, is repeatedly recrystallized 

 from benzene. Small, yellow laminae ; fusing point, 

 245-248; difficultly soluble in alcohol, ether, and car- 

 bon bisulphide; more easily in hot benzene. Treated with 

 picric acid in boiling benzene, it yields a compound, 

 C 18 H 12 4- C 6 H 3 (M) 2 ) 3 0, that crystallizes in brown needles. 

 Citric acid and bromine yield substitution-products. 

 Heated with glacial acetic acid and chromic acid, it is 

 converted into chrysoquinone, C 18 H 10 2 , which crystal- 

 lizes in beautiful red needles, dissolves in cold concen- 

 trated sulphuric acid forming a deep indigo-blue solu- 

 tion, and is reprecipitated from this solution, un- 

 changed, by the addition of water. 



Retene, C 18 H 18 . Is contained in the tar from very 

 resinous pine- and fir-wood ; and is formed together 

 with benzene, cinnamene and other hydrocarbons by 

 heating acetylene. "White laminae of a mother-of-pearl 

 lustre ; fusing point, 98-99 ; difficultly soluble in al- 

 cohol, easily in ether and benzene. Combines with 

 picric acid forming a compound, C 18 II 18 -f C 6 H 3 (^"0 2 ) 3 0, 

 that crystallizes in orange-yellow needles. It dissolves 

 in concentrated sulphuric acid, a crystalline disulpho- 

 acid, C 18 H 16 (S0 2 .OH) 2 , being formed, the barium salt of 

 which crystallizes in colorless needles. When treated 

 with potassium bichromate and dilute sulphuric acid, 

 it yields carbonic anhydride, acetic and phtalic acids, 

 and a brick-red powder, dioxyretistene, C 16 H 14 2 , which 

 crystallizes in long, flat, orange-colored needles ; fuses 

 at 194-195; and, when heated with zinc dust, yields a 

 solid hydrocarbon retistene, C 16 H 14 . 



Fichtelite in old pine trunks, idrialin in the mer- 

 cury-ore of Idria, scheererite in beds of bituminous coal, 

 are similar hydrocarbons, the chemical character of 

 which is but little understood. 



