Ammonium borohydride (NH4BH4) is extremely desirable as a solid hydrogen storage material because of its large hydrogen density by weight on the molecule (24%). Investigations of NH4BH4 have long been neglected since the first studies in the early 1950's by Schultz and others due to the short lifetime of NH4BH4 at standard temperature and pressure. In this work we focus our efforts on the chemical and physical properties of NH4BH4 to evaluate its potential as a hydrogen storage material. Discussed here, is full spectroscopic characterization of NH4BH4 and its degradation product diammoniate of diborane (DADB) using infrared spectroscopy and nuclear magnetic resonance as well as x-ray powder diffraction. Thermal analysis of NH4BH4 and DADB from differential scanning calorimetry and thermal gravimetric analysis coupled with a mass spectrometer is also presented. The stability, solubility, reactivity of NH4BH4 is discussed as well as mechanisms of degradation and hydrogen release.