For the thermochemical study of negative hydride-ion desorption from powdery saline hydride (MHn, n = 1 or 2) deposited on a molybdenum ribbon heater, both negative-ionic and electronic desorption currents from MHn were measured simultaneously as a function of sample temperature (ca. 700-800 K) by using a mass spectrometer, thereby yielding the new data that the desorption energy (E-) of H- and the work function (phi) of the desorbing surface of MHn are, respectively. 536 and 318 kJ mol(-1) for LiH, 728 and 492 kJ mol(-1) for CaH2, and 937 and 702 kJ mol(-1) for SrH2. Our energy cycle, consisting of the four indirect processes equivalent in reaction energy to the direct desorption of H- from MHn, indicates that the theoretical values of E- - phi are 227, 224 and 227 kJ mol(-1) for LiH, CaH2 and SrH2, respectively. They are in good agreement with our respective experimental values of 218, 236 and 235 kJ mol(-1) within the experimental error of ca. +/-5%. This agreement indicates that the desorption of H- from MHn is explained reasonably well by our simple model based on chemical thermodynamics.