Next Article in Journal
Study of Adsorption Mechanism of Congo Red on Graphene Oxide/PAMAM Nanocomposite
Next Article in Special Issue
Exploratory Work in the Quaternary System of Ca–Eu–Cd–Sb: Synthesis, Crystal, and Electronic Structures of New Zintl Solid Solutions
Previous Article in Journal
Surface Modification of Ti-35Nb-10Ta-1.5Fe by the Double Acid-Etching Process
Open AccessArticle

Structure and Chemical Bonding of the Li-Doped Polar Intermetallic RE2In1−xLixGe2 (RE = La, Nd, Sm, Gd; x = 0.13, 0.28, 0.43, 0.53) System

Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 28644, Korea
*
Author to whom correspondence should be addressed.
Materials 2018, 11(4), 495; https://doi.org/10.3390/ma11040495
Received: 12 February 2018 / Revised: 11 March 2018 / Accepted: 20 March 2018 / Published: 26 March 2018
(This article belongs to the Special Issue Advances in Zintl Phases)
Four polar intermetallic compounds belonging to the RE2In1−xLixGe2 (RE = La, Nd, Sm, Gd; x = 0.13(1), 0.28(1), 0.43(1), 0.53(1)) system have been synthesized by the traditional solid-state reaction method, and their crystal structures have been characterized by single-crystal X-ray diffraction (SXRD) analyses. The isotypic crystal structures of four title compounds adopt the Mo2FeB2-type structure having the tetragonal space group P4/mbm (Z = 2, Pearson code tP40) with three crystallographically independent atomic sites and can be simply described as a pile of the identical 2-dimensioanl (2D) RE2In1-xLixGe2 slabs stacked along the c-axis direction. The substituting Li atom shows a particular site preference for replacing In at the Wyckoff 2a site rather than Ge at the Wyckoff 4g in this crystal structure. As the size of a used rare-earth metal decreases from La3+ to Gd3+ throughout the title system, the Ge-Ge and Ge-In/Li bond distances, both of which consist of the 2D anionic Ge2(In/Li) layer, gradually decrease resulting in the reduction of a unit cell volume. A series of theoretical investigations has been performed using a hypothetical structure model Gd2In0.5Li0.5Ge2 by tight-binding linear muffin-tin orbital (TB-LMTO) method. The resultant densities of states (DOS) value at the Fermi level (EF) suggests a metallic conductivity for this particular composition, and this calculation result is in a good agreement with the formal charge distribution assigning two extra valence electrons for a metal-metal bond in the conduction band. The thorough analyses of six crystal orbital Hamilton population (COHP) curves representing various interatomic interactions and an electron localization function (ELF) diagram indicating the locations of paired-electron densities are also provided in this article. View Full-Text
Keywords: polar intermetallics; single crystal X-ray diffraction; site-preference of Li; electronic structure polar intermetallics; single crystal X-ray diffraction; site-preference of Li; electronic structure
Show Figures

Graphical abstract

MDPI and ACS Style

Lee, J.; Jeon, J.; You, T.-S. Structure and Chemical Bonding of the Li-Doped Polar Intermetallic RE2In1−xLixGe2 (RE = La, Nd, Sm, Gd; x = 0.13, 0.28, 0.43, 0.53) System. Materials 2018, 11, 495.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop