skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Flux Growth of La 3 MC 2 ( M  = Sb, Bi, Te), a New Family of Ternary Carbides
Reactions of carbon with a heavy main group metal (M = Sb, Bi, or Te) in an excess of lanthanum/nickel eutectic flux lead to formation of a family of carbide compounds La3MC2with a new structure type. The monoclinic structure features C24−anions octahedrally coordinated by six La3+cations, andManions surrounded by 8 La3+cations. These compounds are not charge‐balanced and lie on the border between intermetallic carbides and mixed anion salts. Density of states calculations show a pseudogap at the Fermi level for La3BiC2, which indicates that this compound is a poor metal with optimized LaBi bonding interactions.  more » « less
Award ID(s):
2126077
PAR ID:
10653237
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Zeitschrift für anorganische und allgemeine Chemie
Volume:
651
Issue:
10
ISSN:
0044-2313
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Bis(triphenylsulfonium) tetrachloridomanganate(II), (C18H15S)2[MnCl4] (I), triphenylsulfonium tetrachloridoferrate(III), (C18H15S)[FeCl4] (II), and bis(triphenylsulfonium) tetrachloridocobaltate(II), (C18H15S)2[CoCl4] (III), crystallize in the monoclinic space groupsP21/n[(I) and (III)] andP21/c[(II)]. Compounds (I) and (III) each contain two crystallographically independent triphenylsulfonium (TPS+) cations in the asymmetric unit, whereas (II) has one. In all three compounds, the sulfonium centers adopt distorted trigonal–pyramidal geometries, with S—C bond lengths falling roughly in the 1.78–1.79 Å range and C—S—C angles observed at about 101 to 106°. The [MCl4]n−anions (M= Mn2+, Fe3+, Co2+;n= 2,1,2) adopt slightly distorted tetrahedral geometries, withM—Cl bond lengths in the 2.19–2.38 Å range and Cl—M—Cl angles of approximately 104–113°. Hirshfeld surface analyses shows that H...H and H...C contacts dominate the TPS+cation environments, whereas H...Cl and shortM—S interactions link each [MCl4]n−anion to the surrounding cations. In (I) and (III), inversion-centered π–π stacking further consolidates the crystal packing, while in (II) no π–π interactions are observed. 
    more » « less
  2. Abstract Antiferromagnetic van der Waals‐typeM2P2X6compounds provide a versatile material platform for studying 2D magnetism and relevant phenomena. Establishing ferromagnetism in 2D materials is technologically valuable. Though magnetism is generally tunable via a chemical way, it is challenging to induce ferromagnetism with isovalent chalcogen and bimetallic substitutions inM2P2X6. Here, we report co‐substitution of Cu1+and Cr3+for Ni2+in Ni2P2S6, creating CuxNi2(1‐x)CrxP2S6medium‐entropy alloys spanning a full substitution range (x= 0 to 1). Such substitution strategy leads to a unique evolution in crystal structure and magnetic phases that are distinct from traditional isovalent bimetallic doping, with Cu and Cr co‐substitution enhancing ferromagnetic correlations and generating a weak ferromagnetic phase in intermediate compositions. This aliovalent substitution strategy offers a universal approach for tuning layered magnetism in antiferromagnetic systems, which along with the potential for light‐matter interaction and high‐temperature ferroelectricity, can enable multifunctional device applications. 
    more » « less
  3. Abstract The X2MH6family, consisting of an electropositive cation Xn+and a main group metal M octahedrally coordinated by hydrogen, have been identified as promising templates for high‐temperature conventional superconductivity. Herein, we analyze the electronic structure of two members of this family, Mg2IrH6and Ca2IrH6, showing why the former may possess superconducting properties rivaling those of the cuprates, whereas the latter does not. Within Mg2IrH6the vibrations of the anions IrH64−anions are key for the superconducting mechanism, and they induce coupling in the set of orbitals, which are antibonding between the H 1sand the Ir or orbitals. Because calcium possesses low‐lyingd‐orbitals, →Cadback‐donation is preferred, quenching the superconductivity. Our analysis explains why high critical temperatures were only predicted for second or third row X metal atoms, and may provide rules for identifying likely high‐temperature superconductors in other systems where the antibonding anionic states are filled. 
    more » « less
  4. Ti3C2TxMXene membranes have attracted considerable interest due to their exceptional water transport properties, yet the role of cation intercalation on governing transport remains poorly understood. In this experimental and theoretical study, it shows how intercalation with K+, Na+, Li+, Ca2+, and Mg2+modulates both the nanochannel architecture and water flux of Ti3C2Txmembranes. Unlike in graphene oxide analogs, cations with larger hydration diameters in Ti3C2Txexpand the interlayer spacing, widening flow channels, enhancing slip length of these nanochannels, and boosting water flux from 31.45 to 61.86 L m−2 h−1. To overcome intrinsically poor adhesion of Ti3C2Txto polymeric supports, this study incorporates a thin polyvinyl‐alcohol interlayer, which substantially enhances mechanical robustness and structural integrity. Together, these findings elucidate how cation hydration controls water transport and offer a flexible strategy for tailoring MXene membrane performance. 
    more » « less
  5. Bis(triphenylsulfonium) tetrachloridozinc(II), (C18H15S)2[ZnCl4] (I), bis(triphenylsulfonium) tetrachloridocadmium(II), (C18H15S)2[CdCl4] (II), and bis(triphenylsulfonium) tetrachloridomercury(II) methanol monosolvate, (C18H15S)2[HgCl4]·CH3OH (III), each crystallize in the monoclinic space groupP21/n. In all three structures, there are two crystallographically independent triphenylsulfonium (TPS) cations per asymmetric unit, each adopting a distorted trigonal–pyramidal geometry about the S atom (S—C bond lengths in the 1.77–1.80 Å range and C—S—C angles of 100–107°). The [MCl4]2–anions (M= Zn2+, Cd2+, Hg2+) are tetrahedral; their M—Cl bond lengths systematically increase from Zn2+to Hg2+, consistent with the larger ionic radius of the heavier metal. Hirshfeld surface analyses show that H...H and H...C contacts dominate the TPS cation environments, whereas H...Cl and S...Minteractions anchor each [MCl4]2–anion to two surrounding TPS cations. Weak C—H...Cl hydrogen bonds, as well as inversion-centered π–π stacking, generate layers in (I) and (II) and dimeric [(TPS)2–HgCl4]2assemblies in (III). 
    more » « less