Bond Lengths and Angles
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Dialog Box: Bond Lengths and Angles [ Control Window ]

This supplies the parameters for the computation of the list of bond or interatomic distances and angles centered on one or all of the input atoms. You can select either original (Old) or transformed (New) atoms. The radio buttons determine whether distances and angles are computed for all input atoms or only the one currently selected in the Control Window or in the edit box.

Only 36 atoms in addition to the central atom are allowed, so the distance limit for central-ligand should normally not be more than about 4 Angstroms. Angles are only calculated for ligand pairs at less then the ligand-ligand limit; if you want to determine angles for atoms on opposite sides of the central atom, the ligand-ligand limit should be twice the central-ligand limit.

The results of the distance and angle calculations are written to a file called either Bonds1.ccd (original atoms) or Bonds2.ccd (transformed atoms) in the home directory (see Files used by CRYSCON), and then shown in a Text window (see Types of Windows ). This window has its own menus for editing and saving the text file. From this Text window, return to the Control window and the ordinary operating mode of CRYSCON by clicking in the Control Window, or with the Window menu.

Errors in bond lengths and angles are not calculated by CRYSCON. This is because sufficient data are seldom available for accurate calculation - it would be necessary to have the complete variance-covariance matrices for both the unit-cell and atomic-parameter refinements. The difference between the correct error values and those calculated using only the standard deviations of the parameters is usually not large, but discrepancies between values in the original publications and those calculated by CRYSCON could create confusion.