382 
DR. A. W. HOFMANN’S RESEARCHES INTO THE 
Iodide of Trimethylammonium 
Iodide of Tetramethylammoniuin 
■ "" 1 
C2 H3 ' 
C2H3 
C2 H3 
NI. 
^C2H3 
C 2 H 3 
C 2 H 3 
C2H3 
>NI. 
Of these five compounds, the first and the last are formed in considerable ex- 
cess. Of the remainder I have as yet only been able to establish the presence of the 
iodide of methylammonium by numbers. The two others I have not as yet obtained 
in sufficiently large quantity and of the requisite purity. The solution of this mixture 
deposits, on cooling, magnificent dazzling-white hard flat needles, sometimes of an 
inch in length, which are very difficultly soluble in cold water, and may be obtained 
in the state of purity by washing with cold and recrystallizing from boiling water. 
These crystals are the iodide of tetramethylammonium, all the other salts remaining 
in the mother-liquor, which rapidly turns brown on exposure to the atmosphere. The 
facility with which ammonia acts upon iodide of methyl, renders it unnecessary to 
perform the process at a high temperature. The reaction is accomplished after some 
days, even at the common temperature, if an alcoholic solution be employed, after 
some hours, a considerable amount of heat being disengaged. 
Iodide of Tetramethylammonium. 
This substance possesses the family-features of the group. It is soluble in water, 
but far less so than the corresponding ethyl-compound, forming a perfectly neutral 
solution of an extremely bitter taste. It is almost insoluble in absolute alcohol, in- 
soluble in ether. Like the ethyl-compounds, this salt is far less soluble in potassa 
than in pure water. 
On analysis the following results were obtained : — 
I. 0*4753 grm. of iodide gave 0*55 19 grm. of iodide of silver. 
II. 0*4256 grm. of iodide gave 0*4973 grm. of iodide of silver. 
Percentage. 
/ ^ . 
I. II. 
Iodine 62*75 63*14 
Cg N I=^ 
H 3 I 
HJ 
C.H 3 
C2 H3J 
The formula 
