Shima Soltani Nezhad

Above 1400 ° C, the mixtures of a 1:1 Gd: Fe atomic ratio tend to form the perovskite (orthoferrite) phase (GdFeO3), whilst the 3:5 mixtures form the garnet phase (Gd3Fe5O12).

https://www.sciencedirect.com/science/article/abs/pii/0167577X9290159H

1. You need to decide the enthalpy of formation of which ferrite you need.

2. write the equation for the formation of the corresponding oxide of gadolinium and iron.

3. In the tables are the standard enthalpies of formation of gadolinium and iron oxide.

4. According to the Hess law and the chemical equation, find the standard enthalpy of formation of gadolinium ferrite.

See and study the thermodynamics of chemical reactions for help.

Data Yu. A. Mirgorod, R.V. Grebennikova. Glossary on Physical Chemistry