CONTRIBUTIONS FROM THE CHEMICAL LABORATORY 

 OF HARVARD COLLEGE. 



FERROUS IODIDE. 



By C. Loring Jackson and I. H. Derby. 



Presented May 10, 1899. Received November 24, 1899. 



The accounts of anhydrous ferrous iodide which we have been able to 

 find in the chemical literature are very contradictory. Serullas * seems 

 to have been the first to obtain it by the rather strange method of passing 

 iodine and steam through a red-hot iron tube filled with charcoal. He 

 describes it as shining yellow crystals looking like gold filings. Gay 

 Lussac and Davy * say it is a brown mass which fuses at a red heat and 

 sublimes at a higher temperature. A. T. Thomson f treated one part 

 of iron with two of iodine suspended in water, and after evaporating off 

 the water in a flask containing some free iron, obtained a steel gray lam- 

 inated mass melting at 177° and possessing a sharp puckery taste. When 

 heated in air it left a residue of ferric oxide. In 1861 Carius and Wank- 

 lyn I prepared it as a gray laminated mass by heating iron filings and 

 iodine in a porcelain crucible. In 1863 De Luca § states that Faville 

 had made it under his direction, and that it is a pure white amorphous 

 powder. He gives no statement of the method of preparation in any of 

 the journals which are accessible to us. Finally Erdmann || in his Lehr- 

 buch (1898) describes it as a reddish brown body, also without giving 

 the method of preparation. The color of ferrous iodide, therefore, is not 

 by any means settled, the balance of evidence in the chemical literature 

 being in favor of gray or white ; but as no analyses of the anhydrous 

 salt have been published, so far as we cau find, none of the statements 

 quoted above can be considered to rest on a solid foundation. Under 



* Gmelin-Kraut, Handbuch, III. 350, 6th edition. 



t Pharmaceut. Journ., I. 44 (1842). 



J Ann. Chem, CXX. 69. 



§ Comptes-Rendus, LV. 615. 



|| Lehrbuch der anorganischen Chemie, 62. 



