Heat Capacity Function, Enthalpy of Formation and Absolute Entropy of Mg(AlH₄ )₂

Area of Science:

• Materials Science
• Thermodynamics
• Solid-state Chemistry

Background:

• Alanates are a class of compounds with potential applications in hydrogen storage.
• Accurate thermodynamic data is crucial for understanding and optimizing alanate properties.
• Existing estimation procedures for alanate thermodynamics require validation and updates.

Purpose of the Study:

• To experimentally determine the thermodynamic properties of magnesium alanate (Mg(AlH4)2).
• To use the obtained data to reevaluate and update existing estimation methods for thermodynamic functions of alanates.
• To provide a reliable dataset for Mg(AlH4)2, including heat capacity, enthalpy of formation, and absolute entropy.

Main Methods:

• Calorimetry was employed to measure the heat capacity of Mg(AlH4)2 over a temperature range of 2 K to 370 K.
• Enthalpy of formation and absolute entropy were determined at standard conditions (298.15 K).
• The experimental data was used to refine predictive models for alanate thermodynamics.

Main Results:

• The heat capacity function of Mg(AlH4)2 was characterized from 2 K to 370 K.
• The enthalpy of formation of Mg(AlH4)2 was determined to be [value] kJ/mol.
• The absolute entropy of Mg(AlH4)2 was found to be 133.06 J/(K·mol) at 298.15 K.

Conclusions:

• The experimental thermodynamic data for Mg(AlH4)2 provides a crucial benchmark.
• Updated estimation procedures enhance the accuracy of thermodynamic predictions for various alanates.
• This work contributes to a better understanding of alanate materials for potential applications.