A novel inorganic hydride compound KHI which comprises a high binding energy hydride ion was synthesized by reaction of atomic hydrogen with potassium metal and potassium iodide. Potassium iodo hydride was identified by time-of-flight secondary ion mass spectroscopy, X-ray photoelectron spectroscopy, H-1 and K-39 nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, electrospray ionization time-of-flight mass spectroscopy, liquid chromatography/mass spectroscopy, thermal decomposition with analysis by gas chromatography, and mass spectroscopy, and elemental analysis. Hydride ions with increased binding energies may form many novel compounds with broad applications. (C) 2000 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.