I am novice to MS, and is learning from tutorial.  I have problems when I follow sorption tutorial: Predicting the loading of ions in Al-substituted zeolite MFI, I am checking here to see whether people has experience on it.  Thanks!

1:  I followed step to calculate forcefield using sorption preparation opetions dialogue.  After making Na atom.xsd the active document and click the calulate button,  I got an error message:

Error : The forcefield type calculation failed.

The last error reported was:

The typing engine has failed to calculate a forcefield type for 2 particles.

Press Yes to select atoms that have not been typed.

Press No to carry on

2: Also the tutorial asks to select 5 Si atoms to be changed to Al atoms.  Nomatter how I choose, it always more than 5 Si atoms picked, looks like some sites are connected.  Is it right?  Thanks!