The molar volume of silicon [Avogadro constant]

A reevaluation has been made of the density and molar mass data for the silicon single crystals used in three Avogadro projects in which the authors' institutions are cooperating. A value of 12.058 825(15) cm/sup 3/ mol/sup -1/ at 22.5/spl deg/C was obtained for the ratio M(Si)//spl rho/(Si), which is considered our present best estimate of the silicon molar volume. This implies for the Avogadro constant a value of 6.022 137 8(75)/spl times/10/sup 23/ mol/sup -1/, with a relative difference of (2/spl plusmn/12)/spl times/10/sup -7/ with respect to the value published by Seyfried et al. (1992).