code: public static IAtomContainer makePyridineOxide() {
          IAtomContainer mol = new AtomContainer();
          mol.addAtom(new Atom("C")); // 0
          mol.addAtom(new Atom("N")); // 1
          mol.getAtom(1).setFormalCharge(1);
          mol.addAtom(new Atom("C")); // 2
          mol.addAtom(new Atom("C")); // 3
          mol.addAtom(new Atom("C")); // 4
          mol.addAtom(new Atom("C")); // 5
          mol.addAtom(new Atom("O")); // 6
          mol.getAtom(6).setFormalCharge(-1);
  
          mol.addBond(0, 1, IBond.Order.DOUBLE); // 1
          mol.addBond(1, 2, IBond.Order.SINGLE); // 2
          mol.addBond(2, 3, IBond.Order.DOUBLE); // 3
          mol.addBond(3, 4, IBond.Order.SINGLE); // 4
          mol.addBond(4, 5, IBond.Order.DOUBLE); // 5
          mol.addBond(5, 0, IBond.Order.SINGLE); // 6
          mol.addBond(1, 6, IBond.Order.SINGLE); // 7
  
          return mol;
      }
docs: Returns pyridine oxide without explicit hydrogens.
  
  @cdk.inchi InChI=1/C5H5NO/c7-6-4-2-1-3-5-6/h1-5H