The Si-route to the Avogadro constant: new measurements of the molar volume and lattice parameter in an integrated international approach

New measurements of the molar volume and lattice parameter of Si, in near-perfect Si crystals, are reported and discussed. These measurements have been planned and performed within a worldwide collaboration coordinated by the CCM working group on the Avogadro constant. The present determination of the molar volume, does confirm the value published previously within stated uncertainty.