Crystal structure of Ti₄Ni₂C

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Titanium-nickel (Ti2Ni) intermetallics are known for their unique properties.
• Previous studies have investigated related oxicarbide and carbide phases using powder diffraction.

Purpose of the Study:

• To report the serendipitous synthesis and structural characterization of a novel Ti4Ni2C intermetallic phase.
• To elucidate the crystallographic relationship between Ti4Ni2C and the parent Ti2Ni structure.

Main Methods:

• High-pressure sintering of Ti2Ni powder mixtures.
• Single crystal X-ray diffraction for structural determination.

Main Results:

• Single crystals of Ti4Ni2C were successfully obtained.
• The Ti4Ni2C phase crystallizes in the Fd-3m space group.
• The structure is a partially filled Ti2Ni framework with carbon atoms in octahedral voids.

Conclusions:

• Ti4Ni2C represents a new intermetallic compound with a distinct crystal structure.
• The carbon atom's placement in octahedral voids significantly influences the structure.
• This finding expands the family of isotypic compounds, including Ti4Ni2O, Nb4Ni2C, and Ta4Ni2C.