(no subject)

Dear Arun,

I create a unit cell of montmorillonite that is has negative charge. First it should be balanced it with Na cations. Afterwards the montmorillonite surface should be contacted with a droplet.

Neda

Dear Arun,

I create a unit cell of montmorillonite that is has negative charge. First
it should be balanced it with Na cations. Afterwards the montmorillonite
surface should be contacted with a droplet.

a regular crystalline unit cell should be neutral. you cannot have a
crystal with charged unit cells, that would be extremely unstable.
so you may have to review your procedure of building that cell.

you may get (a few) unbalanced charges, when building a larger
construct from multiple unit cells when cutting through polar
surfaces.
again, you should review your procedure of building your structure to
minimize them, and then counter ions are most easily placed near the
locations that you know will have an uncompensated surface charge.

since your system is likely to be solvated with water, the simplest
way to insert counter charges is to replace a suitable number of
(randomly chosen) water molecules with your counter ions while placing
the ion at the location of the water oxygen.

axel.