Adsorption of Gases on Quartz Single Crystals

Abstract

Approximate adsorption isotherms of hexane and argon on the crystal face perpendicular to the Y axis of quartz have been obtained, making use of the alteration of the mechanically resonant frequency of a 10‐Mc, Y‐cut quartz crystal as a measure of the mass adsorbed. The ``area'' of the hexane molecule was found to be 50 A² and the heat of adsorption at (B.E.T.) monolayer coverage was 1.5 kcal/mole in excess of the heat of liquefaction. A piezoelectric crystal vibrating in a thickness‐shear mode appears to constitute a microbalance of sensitivity sufficient to permit measurement, in favorable cases, of isotherms on adsorbents of very low specific area.