code: static String chargeAdjunctText(final int charge, final int unpaired) {
          StringBuilder sb = new StringBuilder();
  
          if (unpaired == 1) {
              if (charge != 0) {
                  sb.append('(').append(BULLET).append(')');
              } else {
                  sb.append(BULLET);
              }
          } else if (unpaired > 1) {
              if (charge != 0) {
                  sb.append('(').append(unpaired).append(BULLET).append(')');
              } else {
                  sb.append(unpaired).append(BULLET);
              }
          }
  
          final char sign = charge < 0 ? MINUS : PLUS;
          final int coefficient = Math.abs(charge);
  
          if (coefficient > 1) sb.append(coefficient);
          if (coefficient > 0) sb.append(sign);
  
          return sb.toString();
      }
docs: Create the charge adjunct text for the specified charge and number of unpaired electrons.
  
  @param charge   formal charge
  @param unpaired number of unpaired electrons
  @return adjunct text