BONDCHARACTERS
Jan. 20, 1963
TABLE I1 AMIDE-AMMONIACOMPOUNDS Stability range (% of Probable formula
Transition temp. to amide,
NHa)
NHs.HCONHia 53.5-71 N H ~ * C H X C O N H ~ ~ 68-92 NH3.HCONI-ICHs *.. (metastable) NHs*HCONHCHj (stable) 61-74 NHs.HCON( CHa)t 52-67
O C .
Eutectic temp. with NHs, OC.
M.P., OC.
(by-
extr.)
-75.5 -32
..a
-75
-82
-25
..
-102
-96
-75 -87 a A second addition compound, 2NHa.HCON9, undergoes transition to the 1: 1compound and solution a t -92 ; its eutectic temperature with ammonia is -96’. -82 -w.5
-96 -94
it appears highly probable that each of them consists of amide and ammonia in equimolecular ratio. The NMF-ammonia compound occurs in two modifications, one of which appeared here only as a metastable phase. Stability and melting point data are shown in Table 11, in which the 1 : l compounds of acetamide and formamide with ammonia, reported in previous paper^,^,^ are included for comparison.
Discussion Since the amide-formic acid compounds of Table I are relatively stable a t their melting points and since they are all formally analogous t o ammonium formate, the names by which they are designated in the table appear to be appropriate. It is significant that the sharpness of the maxima in the equilibrium curves,
[CONTRIBUTION FROM
THE
IN PHOSPHORYL COMPOUNDS
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and the steepness of these curves in the region where formic acid is solid phase, both increase in the order formarnide
