Standard deviations of lattice parameters obtained from powder data measurements

A method is described for least-squares refinement of lattice parameters from powder diffraction measurements. Unusual features are: (1) an individual standard error can be assigned to each line, (2) variances and covariances for all parameters are calculated from those errors, (3) the three parameters of a second-degree correction curve are added to the unknowns, and (4) the method uses both the measurements of internal standard lines - if any - and the lines of the substance under investigation for the simultaneous refinement of all unknowns. Because of the last-mentioned feature, the method is especially suitable for measurements obtained from Guinier cameras. The description of a computer program based on this method is added.