A reassessment of the molar volume of silicon and of the Avogadro constant

An "absolute" value for the molar volume of Si in Si single crystals is presented as 12.058 820 7(54) cm/sup 3/ mol/sup -1/ with a relative standard uncertainty of 4.5/spl middot/10/sup -7/. It is argued that the consistency of most of the molar volume determinations is useful for evaluating the quality of the Si single crystals involved. A value for the Avogadro constant is derived as 6.022 133 9(27)/spl middot/10/sup 23/ mol/sup -1/ having a relative standard uncertainty of 4.6/spl middot/10/sup -7/.