XL.Determination of the lattice spacing and of the rhombohedral angle of magnesium carbonate from a microcrystalline powder

Summary A determination of the lattice constants of magnesium carbonate is undertaken with the purpose of securing a more exact measurement of the rhombohedral angle and of the spacing of the member of the calcite series of carbonates farthest away from calcite. The determination is carried out with a microcrystalline powder using an X-ray method previously described by one of the writers. The result is discussed in connexion with recent theoretical calculations of the lattice constants of the isomorphous series of carbonates of calcite type.