Conductivities and Viscosities in Formamid. 



19 



all proportions, neither being soluble to any extent in absolute ether, 

 chloroform, benzol, hexane, etc.; nor do they dissolve appreciably the 

 aromatic hydrocarbons, nitrobenzol, fats, oils, etc. Further similarity 

 maybe traced in their solvent action on metallic salts; thus, in the cold, 

 cobalt and nickel salts yielding solutions in formamid similarly colored 

 with those in water, although in some instances the formamid solutions 

 undergo change in color on warming, which is probably due to a predom- 

 inance of the unionized salt, since formamid undergoes a much sharper 

 decrease in association with rise in temperature than water. 



As Walden has pointed out, the similarity between water and forma- 

 mid is still closer. Phosphorus and sulphur are practically equally 

 insoluble in both, while iodine gives a brownish-yellow solution. 

 Starch is also soluble in formamid, with formation in concentrated solu- 

 tion of a jelly, and on addition of formamid solution of iodine the starch 

 solution turns intensely blue. The color, however, is less permanent 

 than in water, owing to the slow action of the iodine on the solvent. 

 The fluorescent dyes also exhibit like phenomena in formamid and in 

 water, this being particularly marked in the case of eosin. 



TABLE 5. 



Physical constants. 



Water. 



Formamid. 



Molecular weight 18 



Melting-point j 



Boiling-point 760 mm 100 



Density 0/4 9999 



Dielectric constant 81 (Drnde) 2b 



Association factor 30 > 3.81 (Ramsay-Shields). 



K-surface tension 20 to 30 ... 

 Minimum specific conductivity. 

 Average specific conductivity 



working values. 

 Viscosity, 25 



Dissociation of N(C2Hs)4l at 

 V=100. 



4X10- 8 . 

 1.5X10- B . 



0.00891 (Thorpe and 



Rodger) . 

 91 p. ct. 



45 



1.5-2.1 (Walden). 



200-212 



1.151 (Walden, Davis). 



84 (Walden). 



6.18 (Turner and Merry). 



0.65 (Turner and Merry). 



2.8 X10- 6 (Davis and Putnam). 



2.7 X10- 5 (Davis and Putnam). 



0.0324 (Davis). 



93 p. ct. (Walden); 98 

 (Davis and Putnam). 



p. ct. 



Bruni and Mannuelli 1 further show that just as water hydrolyzes the 

 salts of weak bases, such as those of bismuth and antimony, forming 

 unstable basic salts; formamid by a process of aminolysis may form 

 basic salts of these same metals; and Rohler, 2 in extending this work 

 has isolated characteristic basic salts of copper, cobalt, nickel, and 

 zinc. He has also obtained amidates similar to hydrates, of which 

 PbCl2 HCONH 2 is an example, as well as metal formamidates having 

 the general composition Me(HNCOH) 2 . 2HCONH 2 , where Me may be 

 either copper, nickel, cobalt, or zinc. 



In addition to the above, Rohler has noticed the formation of well- 

 defined crystalline compounds of formamid with the halogen acids, 

 corresponding to the well-known mono-, di-, and tri-hydrates. 



'Zeit. Elektrochem. 11, 554 (1905). 



*Ibid., 16. 418 (1910). 



