Correction Together with the Refinement of Lattice Constants

3 Correction Together with the Refinement of Lattice Constants 

In Table 4.13 an example is worked out for the determination of the sample-displacement error without an internal standard. Other errors should be excluded before if possible. For example, the zero-point error should be corrected by using an external standard. If the reflections can be indexed unequivocally (uncertain reflections must be omitted), the sample-displacement error - the most important error changing from sample to sample - can be easily refined with the lattice constants. The author s program, LATCO, refines the lattice constants twice, with and without sample-displacement error, and one has to decide oneself which of the two refinements is to be preferred. The main criterion for accepting the refinement with sample-position error is the size of the error in comparison with its standard deviation it must amount to at least twice the standard deviation. Furthermore jfi should be significantly 

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