Yb14MgSb11 and Ca14MgSb11-New Mg-containing zintl compounds and their structures, bonding, and thermoelectric properties

Yufei Hu, Jian Wang, Airi Kawamura, Kirill Kovnir, Susan M. Kauzlarich

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Magnesium-containing Zintl phase compounds Yb14MgSb11 and Ca14MgSb11 have been prepared by annealing the mixture of the elements at 1075-1275 K. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Single-crystal X-ray data (90 K) were refined for Yb14MgSb11 [a = 16.625(9) Å, c = 22.24(2) Å, V = 6145(8) Å3, and R1/wR2 (0.0194/0.0398)] and Ca14MgSb11 [a = 16.693(2) Å, c = 22.577(5) Å, V = 6291(2) Å3, R1/wR2 (0.0394/0.0907)]. This structure type has been shown to be highly versatile with a large number of phases with the general formula A14MPn11 (A = Ca, Sr, Ba, Yb, Eu; M = Mn, Zn, Nb, Cd, Group 13 elements; Pn = Group 15 elements). The two compounds reported in this paper are the first Mg-containing analogs. Replacing M with Mg, which is divalent with no d-orbitals, probes electronic structure and properties of this structure type. Mg2+ is well-known to prefer tetrahedral geometry and allows for integration of the properties of a main group analog isoelectronic to the transition metal (Mn2+) containing compounds of this structure type. Thermoelectric properties of both compounds were measured from room temperature to 1075 K on fully dense pellets. Yb14MgSb11 shows metallic behavior, whereas Ca14MgSb11 is a semiconductor with a much larger electrical resistivity. The figure of merit reaches 0.32 for Ca14MgSb11 at 1075 K, and 1.02 at 1075 K for Yb14MgSb11, which is a 45% improvement over the reported zT1075K of Yb14MnSb11 prepared from Sn-flux. Density functional band structure calculations on Ca14MgSb11 yield p-type materials with a band gap of ∼0.6 eV and shows Ca and Sb 5p orbitals contributes to the top of valence band. The electron localization function calculations show that Mg and Sb are covalently bonded in MgSb4 9- and that the bonding of Sb3 7- can be considered as a hypervalent 3c-4e bond.

Original languageEnglish (US)
Pages (from-to)343-351
Number of pages9
JournalChemistry of Materials
Volume27
Issue number1
DOIs
StatePublished - Jan 13 2015

Fingerprint

Valence bands
Electronic properties
Band structure
Magnesium
Electronic structure
Transition metals
Energy gap
Single crystals
Annealing
Semiconductor materials
Fluxes
X rays
Geometry
Electrons
Temperature

ASJC Scopus subject areas

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

Yb14MgSb11 and Ca14MgSb11-New Mg-containing zintl compounds and their structures, bonding, and thermoelectric properties. / Hu, Yufei; Wang, Jian; Kawamura, Airi; Kovnir, Kirill; Kauzlarich, Susan M.

In: Chemistry of Materials, Vol. 27, No. 1, 13.01.2015, p. 343-351.

Research output: Contribution to journalArticle

Hu, Yufei ; Wang, Jian ; Kawamura, Airi ; Kovnir, Kirill ; Kauzlarich, Susan M. / Yb14MgSb11 and Ca14MgSb11-New Mg-containing zintl compounds and their structures, bonding, and thermoelectric properties. In: Chemistry of Materials. 2015 ; Vol. 27, No. 1. pp. 343-351.
@article{e9c466d7fdc64f7288dc859d3c8a8060,
title = "Yb14MgSb11 and Ca14MgSb11-New Mg-containing zintl compounds and their structures, bonding, and thermoelectric properties",
abstract = "Magnesium-containing Zintl phase compounds Yb14MgSb11 and Ca14MgSb11 have been prepared by annealing the mixture of the elements at 1075-1275 K. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Single-crystal X-ray data (90 K) were refined for Yb14MgSb11 [a = 16.625(9) {\AA}, c = 22.24(2) {\AA}, V = 6145(8) {\AA}3, and R1/wR2 (0.0194/0.0398)] and Ca14MgSb11 [a = 16.693(2) {\AA}, c = 22.577(5) {\AA}, V = 6291(2) {\AA}3, R1/wR2 (0.0394/0.0907)]. This structure type has been shown to be highly versatile with a large number of phases with the general formula A14MPn11 (A = Ca, Sr, Ba, Yb, Eu; M = Mn, Zn, Nb, Cd, Group 13 elements; Pn = Group 15 elements). The two compounds reported in this paper are the first Mg-containing analogs. Replacing M with Mg, which is divalent with no d-orbitals, probes electronic structure and properties of this structure type. Mg2+ is well-known to prefer tetrahedral geometry and allows for integration of the properties of a main group analog isoelectronic to the transition metal (Mn2+) containing compounds of this structure type. Thermoelectric properties of both compounds were measured from room temperature to 1075 K on fully dense pellets. Yb14MgSb11 shows metallic behavior, whereas Ca14MgSb11 is a semiconductor with a much larger electrical resistivity. The figure of merit reaches 0.32 for Ca14MgSb11 at 1075 K, and 1.02 at 1075 K for Yb14MgSb11, which is a 45{\%} improvement over the reported zT1075K of Yb14MnSb11 prepared from Sn-flux. Density functional band structure calculations on Ca14MgSb11 yield p-type materials with a band gap of ∼0.6 eV and shows Ca and Sb 5p orbitals contributes to the top of valence band. The electron localization function calculations show that Mg and Sb are covalently bonded in MgSb4 9- and that the bonding of Sb3 7- can be considered as a hypervalent 3c-4e bond.",
author = "Yufei Hu and Jian Wang and Airi Kawamura and Kirill Kovnir and Kauzlarich, {Susan M.}",
year = "2015",
month = "1",
day = "13",
doi = "10.1021/cm504059t",
language = "English (US)",
volume = "27",
pages = "343--351",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "1",

}

TY - JOUR

T1 - Yb14MgSb11 and Ca14MgSb11-New Mg-containing zintl compounds and their structures, bonding, and thermoelectric properties

AU - Hu, Yufei

AU - Wang, Jian

AU - Kawamura, Airi

AU - Kovnir, Kirill

AU - Kauzlarich, Susan M.

PY - 2015/1/13

Y1 - 2015/1/13

N2 - Magnesium-containing Zintl phase compounds Yb14MgSb11 and Ca14MgSb11 have been prepared by annealing the mixture of the elements at 1075-1275 K. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Single-crystal X-ray data (90 K) were refined for Yb14MgSb11 [a = 16.625(9) Å, c = 22.24(2) Å, V = 6145(8) Å3, and R1/wR2 (0.0194/0.0398)] and Ca14MgSb11 [a = 16.693(2) Å, c = 22.577(5) Å, V = 6291(2) Å3, R1/wR2 (0.0394/0.0907)]. This structure type has been shown to be highly versatile with a large number of phases with the general formula A14MPn11 (A = Ca, Sr, Ba, Yb, Eu; M = Mn, Zn, Nb, Cd, Group 13 elements; Pn = Group 15 elements). The two compounds reported in this paper are the first Mg-containing analogs. Replacing M with Mg, which is divalent with no d-orbitals, probes electronic structure and properties of this structure type. Mg2+ is well-known to prefer tetrahedral geometry and allows for integration of the properties of a main group analog isoelectronic to the transition metal (Mn2+) containing compounds of this structure type. Thermoelectric properties of both compounds were measured from room temperature to 1075 K on fully dense pellets. Yb14MgSb11 shows metallic behavior, whereas Ca14MgSb11 is a semiconductor with a much larger electrical resistivity. The figure of merit reaches 0.32 for Ca14MgSb11 at 1075 K, and 1.02 at 1075 K for Yb14MgSb11, which is a 45% improvement over the reported zT1075K of Yb14MnSb11 prepared from Sn-flux. Density functional band structure calculations on Ca14MgSb11 yield p-type materials with a band gap of ∼0.6 eV and shows Ca and Sb 5p orbitals contributes to the top of valence band. The electron localization function calculations show that Mg and Sb are covalently bonded in MgSb4 9- and that the bonding of Sb3 7- can be considered as a hypervalent 3c-4e bond.

AB - Magnesium-containing Zintl phase compounds Yb14MgSb11 and Ca14MgSb11 have been prepared by annealing the mixture of the elements at 1075-1275 K. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Single-crystal X-ray data (90 K) were refined for Yb14MgSb11 [a = 16.625(9) Å, c = 22.24(2) Å, V = 6145(8) Å3, and R1/wR2 (0.0194/0.0398)] and Ca14MgSb11 [a = 16.693(2) Å, c = 22.577(5) Å, V = 6291(2) Å3, R1/wR2 (0.0394/0.0907)]. This structure type has been shown to be highly versatile with a large number of phases with the general formula A14MPn11 (A = Ca, Sr, Ba, Yb, Eu; M = Mn, Zn, Nb, Cd, Group 13 elements; Pn = Group 15 elements). The two compounds reported in this paper are the first Mg-containing analogs. Replacing M with Mg, which is divalent with no d-orbitals, probes electronic structure and properties of this structure type. Mg2+ is well-known to prefer tetrahedral geometry and allows for integration of the properties of a main group analog isoelectronic to the transition metal (Mn2+) containing compounds of this structure type. Thermoelectric properties of both compounds were measured from room temperature to 1075 K on fully dense pellets. Yb14MgSb11 shows metallic behavior, whereas Ca14MgSb11 is a semiconductor with a much larger electrical resistivity. The figure of merit reaches 0.32 for Ca14MgSb11 at 1075 K, and 1.02 at 1075 K for Yb14MgSb11, which is a 45% improvement over the reported zT1075K of Yb14MnSb11 prepared from Sn-flux. Density functional band structure calculations on Ca14MgSb11 yield p-type materials with a band gap of ∼0.6 eV and shows Ca and Sb 5p orbitals contributes to the top of valence band. The electron localization function calculations show that Mg and Sb are covalently bonded in MgSb4 9- and that the bonding of Sb3 7- can be considered as a hypervalent 3c-4e bond.

UR - http://www.scopus.com/inward/record.url?scp=84921417344&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84921417344&partnerID=8YFLogxK

U2 - 10.1021/cm504059t

DO - 10.1021/cm504059t

M3 - Article

AN - SCOPUS:84921417344

VL - 27

SP - 343

EP - 351

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 1

ER -