MgNi₂B₆ as a new representative of the CeCr₂B₆ structure type

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Ternary borides are crucial in materials science for their diverse structures and properties.
• Understanding the crystal structure and electronic properties of novel borides is key to discovering new functionalities.

Purpose of the Study:

• To characterize the crystal structure of the ternary boride MgNi₂B₆.
• To investigate the electronic structure and hydrogen absorption properties of MgNi₂B₆.

Main Methods:

• X-ray crystallography to determine the crystal structure.
• Tight-binding linear muffin-tin orbital atomic spheres approximation (TB-LMTO-ASA) for electronic structure calculations.
• Hydrogen absorption measurements.

Main Results:

• MgNi₂B₆ crystallizes in the CeCr₂B₆ structure type.
• Mg atoms are in hexagonal prisms, Ni atoms in 10-vertex polyhedra, and B atoms in trigonal prisms.
• Electronic structure calculations revealed higher electron concentration around B atoms forming channels filled with Mg and Ni.
• Maximum hydrogen absorption capacity of 2.38 wt% H₂ was observed.

Conclusions:

• MgNi₂B₆ represents a new structure type with unique atomic coordination and electronic characteristics.
• The electronic structure facilitates hydrogen absorption, indicating potential applications in hydrogen storage.