void processSymmetryOperationsLoopBlock() throws Exception {
    parseLoopParameters(symmetryOperationsFields);
    int nRefs = 0;
    for (int i = propertyCount; --i >= 0;)
      if (propertyReferenced[i])
        nRefs++;
    if (nRefs != 1) {
      logger
          .log("?que? _symmetry_equiv or _space_group_symop property not found");
      skipLoop();
      return;
    }
    while (tokenizer.getData()) {
      for (int i = 0; i < fieldCount; ++i) {
        String field = loopData[i];
        if (field.length() == 0)
          continue;
        char firstChar = field.charAt(0);
        if (firstChar == '\0')
          continue;
        switch (fieldTypes[i]) {
        case SYMOP_XYZ:
        case SYM_EQUIV_XYZ:
          setSymmetryOperator(field);
          break;
        }
      }
    }
  }