String getMolecularFormula() {
			String mf = "";
			String sep = "";
			int nX;
			for (int i = 1; i <= elementNumberMax; i++) {
				nX = elementCounts[i];
				if (nX != 0) {
					mf += sep + JmolConstants.elementSymbolFromNumber(i) + " " + nX;
					sep = " ";
				}
			}
			for (int i = 1; i <= altElementMax; i++) {
				nX = altElementCounts[i];
				if (nX != 0) {
					mf += sep + JmolConstants.elementSymbolFromNumber(JmolConstants.altElementNumberFromIndex(i)) + " "
							+ nX;
					sep = " ";
				}
			}
			return mf;
		}