CrystalMaker Guide: Measuring Distances & Angles

Measuring distances &angles

The toolbar contains various tools which let you measure individual distances and angles in your structure:-

Bond Distance: measures distances between the centres of atoms.

In-plane distance: measures distances in the plane of the plot (i.e., not 3D)

Bond Angle: for three atoms, A-B-C, returns the included angle between the vectors A-B and B-C.

Torsion Angle: for four atoms, A-B-C-D, selected in that order, the torsion angle is the angle between the two vectors: A-B and C-D.

In-plane angle: measure angles in the plane of the plot (i.e., not 3D)

Generating a Bond Distance/Angle Report File

The File > Export > Bond Data command generates a text file containing a listing of all the atoms in the currently-displayed structure, plus a summary of bond distances and angles for each of the crystallographic sites.

Performing a Bond Search

You can display a summary of bond distances around a specified site, or group of sites, using the Transform > List Bonds command.

For crystals:-

• A dialog box prompts you to specify which sites to measure from and to define a maximum search radius. After the bond search has been completed, tables of distances are displayed in the Output Window (Windows > Output). (You can opt for a concise output which lists the number of atoms found as a function of distance from the specified central atom(s).)

For molecules:-

• You need to specify which atom to search around, by selecting that atom with the Arrow Tool. The List Bonds command will then display a dialog allowing you to specify a maximum bond search distance.

For crystals and molecules you can search for bonds around any atom by:-

1. Click on the atom with the Info Tool active. A "luggage tag" will appear, with an info button.
2. Click on the info button to display information about any existing bonds.
3. Option-click on info button to start a bond search around that atom.

Measuring Distances and Angles involving Lattice Planes

You can use the Tranform >Lattice Plane command to display a lattice plane in any orientation. You can move the lattice plane through the structure using the Lattice Plane tool . You can also rotate the lattice plane by holding down the option key on your keyboard as you click and drag with the lattice plane tool.

The Transform > Fit Plane Through Points menu command allows you to calculate the best-fit orientation for a lattice plane, passing through a number of selected atoms. The results of the fit, including the orientation of the plane's normal (in terms of its Miller Indices, hkl) are printed in the Output Window.

You can measure angles between lattice planes - included calculated orientations - using the Transform > Calculate Angle command.

You can record the distances between any selected atoms and a displayed lattice plane, using the Transfom > Distance from Plane menu command.

Click here for more information about using Lattice Plane calculations

Main Menu

© 1999 CrystalMaker Software. All rights reserved