THERMODYNAMIC PROPERTIES OF CALCIUM HYDRIDE¹

Systematic First-Principles Study of Binary Metal Hydrides

“…Comparison with calorimetric data of Bronsted 53 and vH data of Curtis and Chiotti. 54 Alkaline earth metals While alkaline metals form a stable monohydride, the alkaline earth metals are known to form stable dihydrides with various prototypes: body-centered orthorhombic BeH 2 for Be, tetragonal TiO 2 for Mg in addition to orthorhombic PbO 2 and cubic PdF 2 at high pressure and orthorhombic Co 2 Si for both Ca (Figure 1-right) and Sr. The calculated ground-states were found in agreement with these observations.…”

Ammonium chloride–metal hydride based reaction cycle for vehicular applications

“…7b). This temperature is considerably lower than that observed for pure CaH2, 51 likely caused by the destabilising effect of the added NH4Cl. The onset of decomposition for CaH2 coincides with the onset of formation of CaHCl (space group P4/nmm) 52 and an unknown phase which are thermally stable up to at least 500 °C.…”

Metal hydrides for concentrating solar thermal power energy storage

“…Commercial synthesis of NaH is achieved using a continuously stirred emulsion of molten sodium and mineral oil during exposure to H2 gas at ~300 o C [35]. The boiling point of mineral oil precludes the application of this technique for CSP applications above ~400 .H2 and ΔSabs = 127.4 J·mol −1 ·K −1 .H2 in the temperature range of 780 to 900 o C [37]. The use of CaH2 as a solar thermal energy storage material was patented in 2010 [38] due to its promising high temperature properties especially its high energy density: over 20 times higher than molten salts.…”