No abstract

No abstract

The vapor pressure of nitrosyl chloride at low temperatures has been measured by Briner and Pylkoff (1) and Trautz and Genvig (4), but their results differ widely over the range -15°C. to -70°C., the maximum difference being 140 mm. at -45°C. Their results are shown in figure 2, in which logic P is plotted against (1/ T) X 104. In view of the discrepancy the determination has been repeated. EXPERIMENTALTo avoid the "tailing" of mercury, Trautz and Genvig placed a thin layer of concentrated sulfuric acid over the mercury in each limb of the U-tube which was used as a null instrument. In the apparatus described below (see figure 1), nitrosyl chloride does not come in contact with a mercury surface, since the pressure is balanced with a glass gauge. Although taps 6 and 7 were exposed to nitrosyl chloride during the measurements, it was found that the vacuum grease used was not attacked for several hours, and it was shown that the pressure was not affected by the grease by sealing off the tubing on the gauge side of taps 6 and 7.