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Title: Synthesis, crystal structures, and physical properties of the new Zintl phases A{sub 21}Zn{sub 4}Pn{sub 18} (A=Ca, Eu; Pn=As, Sb)—Versatile arrangements of [ZnPn{sub 4}] tetrahedra

Abstract

Four new Zintl phases, Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18}, Eu{sub 21}Zn{sub 4}As{sub 18} and Eu{sub 21}Zn{sub 4}Sb{sub 18} have been synthesized by metal flux reactions. Their structures have been established from single-crystal X-ray diffraction. Despite the similar chemical makeup and the identical formulae, the structures of the four compounds are not the same—Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18} and Eu{sub 21}Zn{sub 4}As{sub 18} crystallize in the monoclinic space group C2/m (No. 12, Z=4) with the β-Ca{sub 21}Mn{sub 4}Sb{sub 18} structure type, while Eu{sub 21}Zn{sub 4}Sb{sub 18} adopts the Ba{sub 21}Cd{sub 4}Sb{sub 18} structure type with the orthorhombic space group Cmce (No. 64, Z=8). Both structures are based on ZnAs{sub 4} or ZnSb{sub 4} tetrahedra, linked in slightly different ways, and Ca{sup 2+} and Eu{sup 2+} cations that fill the space between them. The structural relationships between the title compounds and other known ternary phases with intricate structures are discussed. Electrical resistivity measurement on single-crystalline Eu{sub 21}Zn{sub 4}Sb{sub 18} suggests an intrinsic semiconductor behavior with a band gap of ca. 0.2 eV. The temperature dependent DC magnetization measurement on the same material indicates Curie–Weiss paramagnetism in the high-temperature regime, and a spontaneous antiferromagnetic ordering below 8more » K. The calculated effective moments of Eu confirm the divalent Eu{sup 2+} ground state, as expected from the Zintl–Klemm concept. - Graphical abstract: The four new Zintl phases—Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18}, Eu{sub 21}Zn{sub 4}As{sub 18}, and Eu{sub 21}Zn{sub 4}Sb{sub 18}—crystallize in two structure types, showing the versatility in the arrangements of ZnAs{sub 4} and ZnSb{sub 4} tetrahedra. - Highlights: • Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18}, Eu{sub 21}Zn{sub 4}As{sub 18}, and Eu{sub 21}Zn{sub 4}Sb{sub 18} are new compounds in the respective ternary phase diagrams. • They form with structure types, showing the versatility in the arrangements of ZnAs{sub 4} and ZnSb{sub 4} tetrahedra. • For both structures, the valence electron count follows the Zintl–Klemm rules.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
22475698
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 227; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANTIFERROMAGNETISM; ANTIMONIDES; CALCIUM COMPOUNDS; ELECTRIC CONDUCTIVITY; ELECTRONIC STRUCTURE; EUROPIUM COMPOUNDS; GROUND STATES; MAGNETIZATION; MONOCLINIC LATTICES; MONOCRYSTALS; ORTHORHOMBIC LATTICES; PARAMAGNETISM; PHASE DIAGRAMS; SEMICONDUCTOR MATERIALS; SYNTHESIS; TEMPERATURE DEPENDENCE; VALENCE; X-RAY DIFFRACTION; ZINC ARSENIDES

Citation Formats

Suen, Nian-Tzu, Wang, Yi, and Bobev, Svilen, E-mail: bobev@udel.edu. Synthesis, crystal structures, and physical properties of the new Zintl phases A{sub 21}Zn{sub 4}Pn{sub 18} (A=Ca, Eu; Pn=As, Sb)—Versatile arrangements of [ZnPn{sub 4}] tetrahedra. United States: N. p., 2015. Web. doi:10.1016/J.JSSC.2015.03.031.
Suen, Nian-Tzu, Wang, Yi, & Bobev, Svilen, E-mail: bobev@udel.edu. Synthesis, crystal structures, and physical properties of the new Zintl phases A{sub 21}Zn{sub 4}Pn{sub 18} (A=Ca, Eu; Pn=As, Sb)—Versatile arrangements of [ZnPn{sub 4}] tetrahedra. United States. doi:10.1016/J.JSSC.2015.03.031.
Suen, Nian-Tzu, Wang, Yi, and Bobev, Svilen, E-mail: bobev@udel.edu. 2015. "Synthesis, crystal structures, and physical properties of the new Zintl phases A{sub 21}Zn{sub 4}Pn{sub 18} (A=Ca, Eu; Pn=As, Sb)—Versatile arrangements of [ZnPn{sub 4}] tetrahedra". United States. doi:10.1016/J.JSSC.2015.03.031.
@article{osti_22475698,
title = {Synthesis, crystal structures, and physical properties of the new Zintl phases A{sub 21}Zn{sub 4}Pn{sub 18} (A=Ca, Eu; Pn=As, Sb)—Versatile arrangements of [ZnPn{sub 4}] tetrahedra},
author = {Suen, Nian-Tzu and Wang, Yi and Bobev, Svilen, E-mail: bobev@udel.edu},
abstractNote = {Four new Zintl phases, Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18}, Eu{sub 21}Zn{sub 4}As{sub 18} and Eu{sub 21}Zn{sub 4}Sb{sub 18} have been synthesized by metal flux reactions. Their structures have been established from single-crystal X-ray diffraction. Despite the similar chemical makeup and the identical formulae, the structures of the four compounds are not the same—Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18} and Eu{sub 21}Zn{sub 4}As{sub 18} crystallize in the monoclinic space group C2/m (No. 12, Z=4) with the β-Ca{sub 21}Mn{sub 4}Sb{sub 18} structure type, while Eu{sub 21}Zn{sub 4}Sb{sub 18} adopts the Ba{sub 21}Cd{sub 4}Sb{sub 18} structure type with the orthorhombic space group Cmce (No. 64, Z=8). Both structures are based on ZnAs{sub 4} or ZnSb{sub 4} tetrahedra, linked in slightly different ways, and Ca{sup 2+} and Eu{sup 2+} cations that fill the space between them. The structural relationships between the title compounds and other known ternary phases with intricate structures are discussed. Electrical resistivity measurement on single-crystalline Eu{sub 21}Zn{sub 4}Sb{sub 18} suggests an intrinsic semiconductor behavior with a band gap of ca. 0.2 eV. The temperature dependent DC magnetization measurement on the same material indicates Curie–Weiss paramagnetism in the high-temperature regime, and a spontaneous antiferromagnetic ordering below 8 K. The calculated effective moments of Eu confirm the divalent Eu{sup 2+} ground state, as expected from the Zintl–Klemm concept. - Graphical abstract: The four new Zintl phases—Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18}, Eu{sub 21}Zn{sub 4}As{sub 18}, and Eu{sub 21}Zn{sub 4}Sb{sub 18}—crystallize in two structure types, showing the versatility in the arrangements of ZnAs{sub 4} and ZnSb{sub 4} tetrahedra. - Highlights: • Ca{sub 21}Zn{sub 4}As{sub 18}, Ca{sub 21}Zn{sub 4}Sb{sub 18}, Eu{sub 21}Zn{sub 4}As{sub 18}, and Eu{sub 21}Zn{sub 4}Sb{sub 18} are new compounds in the respective ternary phase diagrams. • They form with structure types, showing the versatility in the arrangements of ZnAs{sub 4} and ZnSb{sub 4} tetrahedra. • For both structures, the valence electron count follows the Zintl–Klemm rules.},
doi = {10.1016/J.JSSC.2015.03.031},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 227,
place = {United States},
year = 2015,
month = 7
}
  • The new intermetallic compounds Sr2ZnP2, Sr2 ZnAs2, A2ZnSb2 and A2ZnBi2 (A = Sr, Eu) have been synthesized from the corresponding elements through high-temperature reactions using the flux-growth method. Their structures have been established by singlecrystal and powder X-ray diffraction. In all cases, the X-ray diffraction patterns can be successfully indexed based on hexagonal cells in the space group P63/mmc (no. 194) with lattice parameters in the range a = 4.31 4.73 and c = 7.9 8.55 . The average structure can be described in the ZrBeSi type (Pearson symbol hP6; 3 unique positions) with defects on the zinc site structuremore » refinements indicate that every second zinc position is vacant, i.e., their formula unit is AZn1 xPn with x = 0.5 (A = Sr, Eu; Pn = P, As, Sb, Bi). No stoichiometry breadth was observed, which could imply that a super-structure with a long-range order of the zinc vacancies is plausible and evidence for such was sought using electron diffraction. The results from these experiments, as well as magnetic susceptibility measurements and band structure calculations using the LMTO code are also discussed.« less
  • Through high temperature Pb-flux reactions, two new arsenide Zintl compounds, Ba{sub 3}Zn{sub 2}As{sub 4} and Ba{sub 3}Cd{sub 2}As{sub 4}, were successfully obtained and their structures were accurately determined with Single-Crystal X-ray Diffraction. Both compounds are isotypic to Ba{sub 3}Cd{sub 2}Sb{sub 4} and crystallize in the monoclinic space group C2/m (No=12) with cell parameters of a=16.916(4)/17.089(3) A, b=4.497(1)/4.6076(7) A, c=7.225(2)/7.304(1) A and {beta}=113.147(2)/112.312(1) Degree-Sign for Ba{sub 3}Zn{sub 2}As{sub 4} and Ba{sub 3}Cd{sub 2}As{sub 4}, respectively. Electrical resistivity measurement on Ba{sub 3}Cd{sub 2}As{sub 4} reveals semiconducting behavior between 10 and 100 K, which results in a very small band gap of 0.01more » eV. According to TG/DSC analyses, Ba{sub 3}Cd{sub 2}As{sub 4} exhibits good thermal stability and does not decompose below 950 K. - Graphic abstract: A polyhedral view of the crystal structure for Ba{sub 3}T{sub 2}As{sub 4} (T=Zn or Cd) in which Ba and As atoms are plotted as purple and red spheres, respectively. Highlights: Black-Right-Pointing-Pointer Two new ternary Zintl compounds, Ba{sub 3}Zn{sub 2}As4 and Ba{sub 3}Cd{sub 2}As{sub 4}, have been synthesized. Black-Right-Pointing-Pointer Their structure features polyanionic layers constructed through [MAs{sub 4}] tetrahedra. Black-Right-Pointing-Pointer Ba{sub 3}Cd{sub 2}As{sub 4} has a very narrow band gap of 0.01 eV and are thermally stable up to 950 K.« less
  • Reported are the syntheses, crystal structure determinations from single-crystal X-ray diffraction, and magnetic properties of two new ternary compounds, Eu{sub 11}Cd{sub 6}Sb{sub 12} and Eu{sub 11}Zn{sub 6}Sb{sub 12}. Both crystallize with the complex Sr{sub 11}Cd{sub 6}Sb{sub 12} structure type-monoclinic, space group C2/m (no. 12), Z=2, with unit cell parameters a=31.979(4) A, b=4.5981(5) A, c=12.3499(14) A, {beta}=109.675(1){sup o} for Eu{sub 11}Zn{sub 6}Sb{sub 12}, and a=32.507(2) A, b=4.7294(3) A, c=12.4158(8) A, {beta}=109.972(1){sup o} for Eu{sub 11}Cd{sub 6}Sb{sub 12}. Their crystal structures are best described as made up of polyanionic {sub {infinity}}{sup 1}[Zn{sub 6}Sb{sub 12}]{sup 22-} and {sub {infinity}}{sup 1}[Cd{sub 6}Sb{sub 12}]{sup 22-}more » ribbons of corner-shared ZnSb{sub 4} and CdSb{sub 4} tetrahedra and Eu{sup 2+} cations. A notable characteristic of these structures is the presence of Sb-Sb interactions, which exist between two tetrahedra from adjacent layers, giving rise to unique channels. Detailed structure analyses shows that similar bonding arrangements are seen in much simpler structure types, such as Ca{sub 3}AlAs{sub 3} and Ca{sub 5}Ga{sub 2}As{sub 6} and the structure can be rationalized as their intergrowth. Temperature-dependent magnetization measurements indicate that Eu{sub 11}Cd{sub 6}Sb{sub 12} orders anti-ferromagnetically below 7.5 K, while Eu{sub 11}Zn{sub 6}Sb{sub 12} does not order down to 5 K. Resistivity measurements confirm that Eu{sub 11}Cd{sub 6}Sb{sub 12} is poorly metallic, as expected for a Zintl phase. - Graphical abstract: The synthesis, structure determination from single-crystal X-ray diffraction and magnetic properties of Eu{sub 11}Zn{sub 6}Sb{sub 12} and Eu{sub 11}Cd{sub 6}Sb{sub 12} are reported. Both compounds crystallize with the monoclinic space group C2/m, and their structure can be viewed as built of ZnSb{sub 4} or CdSb{sub 4} tetrahedra, which are connected through common corners and exo-bonds.« less