Models Miedema, calculated heats

Miedema model calculated heats vs. experimental heats of formation,... 

Where, from fitting experimental values, the parameters a and p are determined to be equal to 29.62 kj eV (molH) and —135 kj (molH) , respectively [71, 72]. This model could also be applied to ternary hydrides with an agreement with experimental values that is generally better than Miedema s model. Figure 4.5 shows a comparison between experimental and calculated heats of formation for various ternary... 

Miedema s model is an empirical theory for calculating heat of mixing in various binary systems both for the solid state (Miedema et al., 1975) and liquid (Boom et al., 1976). This model involves the calculations of the formation enthalpy of metallic glasses (amorphous... 

Miedema and coworkers have developed a model which gives reasonably good agreement between calculated and experimental heat of formation [67-70]. Consider a binary alloy AB where element A easily forms a hydride and element B does not form a hydride. Element A forms a hydride following the reaction... 

In addition to the experimental thermodynamic values, Niessen and de Boer (1981) calculated the enthalpies of formation at 0 K according to a semiempirical model proposed by Miedema et al. (1980) for the carbides R2C, RC and RC2, where R = La, Sc, Y,AHf, room temperature = 99,132 and 111 for La2C, Sc2CandY2C 100,132 and 112 for LaC, ScC and YC 180, 210 and 192(kJmol ) for LaC2, ScC2 and YC2, respectively. Comparison of the predicted heats of formation for LaC2 and YC2 with the experimental values shows these predicted values to be inaccurate by about 100%. 

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