THE DIELECTRIC CONSTANT OF LIQUID ARSINE BY HERMAN SCHLUNDT AND 0. C. SCHAEFER
The dielectric constants of solid ammonia, liquid phosphine and stibine were reported in an earlier communication. We have now determined the dielectric capacity of liquid arsine and have thus completed the values for this series of hydrides. The measurements were made with the Schmidt modificationZ of the Drude apparatus for determining dielectric capacities. The cells were of the U-form similar to those used formerly. They were calibrated with the standard solutions of benzene and acetone just before and after the sample of liquid arsine was measured. Two independent determinations were made with different samples of arsine and. in cells whose dielectric capacity differed somewhat. The stationary electric waves produced by the apparatus in air measured 7 2 cm. The samples of arsine were prepared by the method of Saunders:4 Dilute sulphuric acid was allowed to flow slowly from a drop funnel on an alloy of'sodium and arsenic contained in a suitable generator. The gases evolved were passed through a phosphorus pentoxide tower and the arsine was condensed in a receiver immersed in a bath of solid carbon dioxide and ether, which could be kept under greatly reduced pressure. From the receiver the liquid arsine was distilled directly into the measuring cells, which were then sealed off. The generator, drying trains, condenser, measuring cell, manometers, etc., were sealed together, and the entire apparatus was exhausted to 0 . 1 mm before arsine was generated. The dielectric capacity was measured a t 15' and at approximately -70°, the liquid arsine being under its own Palmer and Schlundt: Jour. Phys. Chem.,
* Drude's Ann., 9, 919 (1902). Jour. Phys. Chem., 13,671 (1909). Chem. News, 79, 66 (1899).
15, 381
(1911).
Herman Schlundt and 0. C. Sclzaefer
254
vapor pressure. Two values'ywere obtained with different cells a t 15' and these were the same, namely 2 . 0 5 , but at about -70' the values were respectively 2.66 and 2.83. The dielectric constant thus increases approximately 0.4 percent per degree cooling below 15 '. The following table gives the dielectric constants of this group of liquid hydrides a t --soo and 15'.
Ammonia Phosphine Arsine Stibine
1
22.7
2.6 2.58 2.58
15.9
2.88l 2.05
I '81'
Chemical Laboratory, University of Missouri, January, 1912 I
Extrapolated. Cf. Jour. Phys. Chem., 15, 381 (1911).
