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New quaternary carbide Mg 1.52 Li 0.24 Al 0.24 C 0.86 as a disorder derivative of the family of hexagonal close‐packed (hcp) structures and the effect of structure modification on the electrochemical behaviour of the electrode
Author(s) -
Pavlyuk Volodymyr,
Kulawik Damian,
Ciesielski Wojciech,
Pavlyuk Nazar,
Dmytriv Grygoriy
Publication year - 2018
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618002851
Subject(s) - carbide , crystallography , materials science , lithium (medication) , octahedron , metal , magnesium , ternary operation , inorganic chemistry , crystal structure , chemistry , metallurgy , medicine , endocrinology , computer science , programming language
Magnesium alloys are the basis for the creation of light and ultra‐light alloys. They have attracted attention as potential materials for the accumulation and storage of hydrogen, as well as electrode materials in metal‐hydride and magnesium‐ion batteries. The search for new metal hydrides has involved magnesium alloys with rare‐earth transition metals and doped by p ‐ or s ‐elements. The synthesis and characterization of a new quaternary carbide, namely dimagnesium lithium aluminium carbide, Mg 1.52 Li 0.24 Al 0.24 C 0.86 , belonging to the family of hexagonal close‐packed (hcp) structures, are reported. The title compound crystallizes with hexagonal symmetry (space group P m 2), where two sites with m 2 symmetry and one site with 3 m . symmetry are occupied by an Mg/Li statistical mixture (in Wyckoff position 1 a ), an Mg/Al statistical mixture (in position 1 d ) and C atoms (2 i ). The cuboctahedral coordination is typical for Mg/Li and Mg/Al, and the C atom is enclosed in an octahedron. Electronic structure calculations were used for elucidation of the ability of lithium or aluminium to substitute magnesium, and evaluation of the nature of the bonding between atoms. The presence of carbon in the carbide phase improves the corrosion resistance of the Mg 1.52 Li 0.24 Al 0.24 C 0.86 alloy compared to the ternary Mg 1.52 Li 0.24 Al 0.24 alloy and Mg.