Accurate Avogadro constant may help redefine the kilogram
Wednesday, October 20, 2010 - 06:00
in Physics & Chemistry
(PhysOrg.com) -- A new accurate determination of the Avogadro constant has used the method of "counting" the atoms in a 1 kg sample of an almost perfect silicon sphere highly enriched with the isotope 28Si. They used isotope dilution mass spectroscopy to determine the molar mass of the silicon with unprecedented accuracy, and this enabled them to obtain the most accurate value for the Avogadro constant ever obtained.