Hydrogen Bonds (IMAGE) University of Basel Caption A hydrogen bond forms between a propellane (lower molecule) and the carbon monoxide functionalized tip of an atomic force microscope. The measured forces and the distance between the oxygen atom at the AFM tip and the propellane's hydrogen atoms correspond precisely to the calculations. Credit University of Basel, Department of Physics Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.