search site  |  contact us  HOME PRODUCTS DOWNLOADS SALES SUPPORT NEWS CrystalMaker Advice Centre   How can I get error bars for bond distances? CrystalMaker will calculate error values for bond distances, if you have provided error values for the unit cell parameters and/or the fractional coordinates for atoms in the asymmetric unit. The best way to get error information into CrystalMaker is to read in a CrystalMaker text file that contains the error values (see Appendix B: CrystalMaker Text Format in the CrystalMaker User's Guide). You will need to have an ERRS card followed by the errors in the structural data, and also an ERRC card, followed by the errors in the cell parameters. Here is a crude example:- TITL Test file! NOTE This is a test to demonstrate error propagation... CELL 10 10 10 90 90 90 ! ! NOTE the "ERRC" card: errors in the unit ! cell parameters; I've guessed these errors - ! they're probably bigger than the true errors! ! ERRC 1.0 0.0 0.0 0.0 0.0 0.0 ! SPGR P 1 XYZR 0.9000 2.1000 0.9000 2.1000 0.9000 2.1000 MODL 1 BKCL 0.58061 0.65992 1.00000 SHCL 1 COLS 1 TYPE Si 0.40 0.6043 0.6043 1.0000 O 1.21 1.0000 0.0000 0.0000 ATOM Si T1 0 0 0 O Oz 0.5 0.0 0.0 ! ! Note the new "errors" line: The syntax is: ! {site label} {sigma x} {Sigma y} {sigma z} ! ERRS T1 0.1 0.1 0.1 Oz 0.0 0.0 0.0 You can then read the text file into CrystalMaker, using the File > Open command. You can display errors by:- option-clicking with the bond distance or bond angle tools (Output is printed, with errors in the Output Window). creating a bonds summary file, using the File > Export > Bond Data command. (An output file is created, containing detailed information about bond distances and angles, with their errors. Note that the maximum bond distances printed in this file correspond to the maximum value in the Transform > List Bonds window.) © 2008 CrystalMaker Software Limited. All rights reserved worldwide.