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Thesis - Open Access

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Master of Science (MS)

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The purpose of this work was to determine the vapor pressure of scandium chloride. The scandium chloride was prepared by heating a mixture of ScCl3. 6H2O and NH4Cl under vacuum. The measurements on the resultant scandium chloride were made with a magnetically controlled microbalance. The system was evacuated to about 2 x 10-6 torr during the determinations. Calibration, in terms of milligrams per millivolt, of the balance was obtained by weighing quartz effusion cells containing mercury before and after effusion and dividing the change in weight by the change in potential necessary to balance the cells before and after effusion. Calibration values also were obtained by using analytical weights. Vapor pressures of mercury and zinc were calculated as a check on the reliability of the data the balance yielded. During the scandium Chloride vapor pressure trials, the formation of scandium oxychloride was found to occur from the hydration and hydrolysis of scandium chloride. The scandium oxychloride remained in the quartz sample cells as a nonvolatile residue as a result of the effusion of scandium chloride from a mixture of scandium chloride and scandium oxychloride. An attempt to measure the- vapor pressure or a substance simultaneously with its molecular weight was inconclusive. A lid device that slid over the orifice of the effusion cell was used in· this particular investigation.

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South Dakota State University