code: protected static double deltavSulphur(IAtom atom, IAtomContainer atomContainer) {
          if (!atom.getSymbol().equals("S")) return -1;
  
          // check whether it's a S in S-S
          List<IAtom> connected = atomContainer.getConnectedAtomsList(atom);
          for (IAtom connectedAtom : connected) {
              if (connectedAtom.getSymbol().equals("S")
                      && atomContainer.getBond(atom, connectedAtom).getOrder() == IBond.Order.SINGLE) return .89;
          }
  
          int count = 0;
          for (IAtom connectedAtom : connected) {
              if (connectedAtom.getSymbol().equals("O")
                      && atomContainer.getBond(atom, connectedAtom).getOrder() == IBond.Order.DOUBLE) count++;
          }
          if (count == 1)
              return 1.33; // check whether it's a S in -SO-
          else if (count == 2) return 2.67; // check whether it's a S in -SO2-
  
          return -1;
      }
docs: Evaluates the empirical delt V for some S environments.
  
  The method checks to see whether a S atom is in a -S-S-,
  -SO-, -SO2- group and returns the empirical values noted
  in Kier & Hall (1986), page 20.
  
  @param atom          The S atom in question
  @param atomContainer The molecule containing the S
  @return The empirical delta V if it is present in one of the above
  environments, -1 otherwise