Evaluating the precision of the data.

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Return to the histogram by clicking on the Results and analysis tab. How confident are you that the Mean of the bond length distribution is an accurate estimate of a typical Sb-Cl bond length? In other words, since we are dealing with real data, might the results be influenced by experimental errors in individual observations?

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The precision with which Mogul can predict molecular dimensions will be determined by the dispersion of the geometry distributions it produces. The reported Standard deviation of the distribution therefore serves as a measure of the precision of those measurements. A large Standard deviation would indicate that the data points are far from the mean and a small Standard deviation would indicate that they are clustered closely around the mean.

•	The Standard deviation of the Sb-Cl bond length distribution is reported under the Statistics listed on the left-hand side of the window. With a value around 0.06Å, the Standard deviation is higher than we would like.

•	The high Standard deviation is due to a number of severe outliers in the distribution i.e. CSD structures have unusually short or long Sb-Cl bond lengths.

•	What are the minimum and maximum Sb-Cl bonds lengths observed in the CSD? Are these observations valid, or could they be from structures that contain experimental errors?