Source code:
@Grab(group='org.openscience.cdk', module='cdk-bundle', version='2.9')
import org.openscience.cdk.interfaces.*;
import org.openscience.cdk.*;
salt = new Crystal();
sodium = new Atom("Na");
sodium.setFormalCharge(+1);
chloride = new Atom("Cl");
chloride.setFormalCharge(-1);
salt.addAtom(sodium);
salt.addAtom(chloride);
Output: