@Test
public void testIronChloride() throws InvalidSmilesException, CDKException {

    IAtomContainer ironChloride = new SmilesParser(SilentChemObjectBuilder.getInstance()).parseSmiles("Cl[Fe]Cl");
    Assert.assertEquals(Double.NaN, ((DoubleResult) descriptor.calculate(ironChloride).getValue()).doubleValue(),
            0.01);
}