Flotation measurements to reveal the reason for the discrepancy in the molar volume of silicon

Silicon single crystals are used to determine the Avogadro constant on the basis of the ratio of molar volume and atomic volume. To reveal the reason for the discrepancy in the molar volume of silicon found in crystals of different origin, the densities of crystals grown under different conditions were compared using a flotation method. The method and the results obtained are reported and the uncertainty is discussed.