Unlike alkenyl hydrogens, alkynyl hydrogens give rise to shielded hydrogens, or relatively high field chemical shifts for H-NMR when subjected to an external magnetic field. This can be explained by the cylindrical pi cloud around the carbon-carbon triple bond. Long range coupling is also observed in the alkynes. Infrared spectroscopy is a useful complement to NMR data, and displays characteristic peaks for terminal and internal alkynes.