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Susan M Kauzlarich - One of the best experts on this subject based on the ideXlab platform.
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high seebeck coefficient and unusually low thermal conductivity near ambient temperatures in layered compound yb2 xeuxcdsb2
Chemistry of Materials, 2018Co-Authors: Joya A Cooley, Phichit Promkhan, Shruba Gangopadhyay, Davide Donadio, W E Pickett, Brenden R Ortiz, Eric S Toberer, Susan M KauzlarichAbstract:Zintl Phases are promising thermoelectric materials because they are composed of both ionic and covalent bonding, which can be independently tuned. An efficient thermoelectric material would have regions of the structure composed of a high-mobility compound semiconductor that provides the “electron–crystal” electronic structure, interwoven (on the atomic scale) with a phonon transport inhibiting structure to act as the “phonon–glass”. The phonon–glass region would benefit from disorder and therefore would be ideal to house dopants without disrupting the electron–crystal region. The solid solution of the Zintl Phase, Yb2–xEuxCdSb2, presents such an optimal structure, and here we characterize its thermoelectric properties above room temperature. Thermoelectric property measurements from 348 to 523 K show high Seebeck values (maximum of ∼269 μV/K at 523 K) with exceptionally low thermal conductivity (minimum ∼0.26 W/m K at 473 K) measured via laser flash analysis. Speed of sound data provide additional suppo...
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Eu11Zn4Sn2As12: A Ferromagnetic Zintl Semiconductor with a Layered Structure Featuring Extended Zn4As6 Sheets and Ethane-like Sn2As6 Units
2018Co-Authors: Kasey P. Devlin, Nasrin Kazem, James C Fettinger, Joya A Cooley, Julia V Zaikina, Jackson R. Badger, Valentin Taufour, Susan M KauzlarichAbstract:We report the synthesis, structure, and magnetic properties of a new Zintl Phase and structure type, Eu11Zn4Sn2As12. The structure and composition of this Phase have been established by single-crystal X-ray diffraction and electron microprobe analysis. Eu11Zn4Sn2As12 crystallizes in monoclinic space group C2/c (No. 15) with the following lattice parameters: a = 7.5679(4) Å, b = 13.0883(6) Å, c = 31.305(2) Å, and β = 94.8444(7)° [R1 = 0.0398; wR2 = 0.0633 (all data)]. The anisotropic structural features staggered ethane-like [Sn2As6]12– units and infinite ∞2[Zn2As3]5– sheets extended in the a–b plane. Eu cations fill the space between these anionic motifs. Temperature-dependent magnetic properties and magnetoresistance of this Zintl Phase have been studied, and the electronic structure and chemical bonding were elucidated using first-principles quantum chemical calculations (TB-LMTO-ASA). Quantum chemical calculations show that the ethane-like units can be considered as consisting of covalent single bonds; however, the ∞2[Zn2As3]5– sheets are best described with delocalized bonding and there is evidence of Eu–As interactions. Temperature-dependent magnetization and transport properties between 2 and 300 K show a ferromagnetic transition at 15 K, a band gap of 0.04 eV, and negative colossal magnetoresistance
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effect of isovalent substitution on the structure and properties of the Zintl Phase solid solution eu7cd4sb8 xasx 2 x 5
ChemInform, 2016Co-Authors: Joya A Cooley, Nasrin Kazem, James C Fettinger, Julia V Zaikina, Susan M KauzlarichAbstract:Eu7Cd4Sb8-xAsx (x = 2, 3, 4, and 5) solid solutions are prepared from the elements in a molten Sn flux (alumina crucible in evacuated silica tubes, 1.
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thermoelectric properties of Zintl antimonides
Handbook on The Physics and Chemistry of Rare Earths, 2016Co-Authors: Nasrin Kazem, Susan M KauzlarichAbstract:Abstract Enhancing the efficiency of thermoelectric devices is critical for their adoption in commercial large-scale applications aimed at converting heat into electricity. To compete with the present mechanical energy generators, thermoelectric materials need to be at least three times more efficient than today's commercial thermoelectrics. This high conversion efficiency corresponds to a thermoelectric figure of merit, zT , of ~ 3, which has remained elusive despite a long history of searching for new thermoelectric materials. The recent discoveries of high zT among Zintl Phase compounds such as Yb 14 MnSb 11 , EuZn 2 Sb 2 , Yb 9 Mn 4.2 Sb 9 , clathrates, and the filled skutterudites show the potential of this class of compounds for more efficient thermoelectric materials. This perspective summarizes the recent progress on Zintl Phases studied for thermoelectric applications with a focus on their chemistry, crystal structure, and transport properties.
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Phase Characterization, Thermal Stability, High-Temperature Transport Properties, and Electronic Structure of Rare-Earth Zintl Phosphides Eu3M2P4 (M = Ga, In)
2016Co-Authors: Gaigong Zhang, Jeffrey G Snyder, Alex Zevalkink, Jeanpierre Fleurial, Naohito Tsujii, Niels Grønbech-jensen, Susan M KauzlarichAbstract:Two rare-earth-containing ternary phosphides, Eu3Ga2P4 and Eu3In2P4, were synthesized by a two-step solid-state method with stoichiometric amounts of the constitutional elements. Refinements of the powder X-ray diffraction are consistent with the reported single-crystal structure with space group C2/c for Eu3Ga2P4 and Pnnm for Eu3In2P4. Thermal gravimetry and differential scanning calorimetry (TG-DSC) measurements reveal high thermal stability up to 1273 K. Thermal diffusivity measurements from room temperature to 800 K demonstrate thermal conductivity as low as 0.6 W/m·K for both compounds. Seebeck coefficient measurements from room temperature to 800 K indicate that both compounds are small band gap semiconductors. Eu3Ga2P4 shows p-type conductivity and Eu3In2P4 p-type conductivity in the temperature range 300–700 K and n-type conductivity above 700 K. Electronic structure calculations result in band gaps of 0.60 and 0.29 eV for Eu3Ga2P4 and Eu3In2P4, respectively. As expected for a valence precise Zintl Phase, electrical resistivity is large, approximately 2600 and 560 mΩ·cm for Eu3Ga2P4 and Eu3In2P4 at room temperature, respectively. Measurements of transport properties suggest that these Zintl phosphides have potential for being good high-temperature thermoelectric materials with optimization of the charge carrier concentration by appropriate extrinsic dopants
Ling Chen - One of the best experts on this subject based on the ideXlab platform.
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a ferrimagnetic Zintl Phase pr4mnsb9 synthesis structure and physical properties
ChemInform, 2013Co-Authors: Xiong Chen, Jinni Shen, Ling ChenAbstract:The title compound is synthesized by solid state reaction of stoichiometric mixtures of the elements (sealed carbon-coated silica tube; 1373 K, 20 h).
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a ferrimagnetic Zintl Phase pr4mnsb9 synthesis structure and physical properties
Inorganic Chemistry, 2013Co-Authors: Xiong Chen, Jinni Shen, Ling ChenAbstract:A new valence precise Zintl Phase, Pr4MnSb9, has been successfully synthesized by solid-state reaction at high temperature. The single-crystal X-ray diffraction data reveal its monoclinic symmetry in the space group C2/m (No. 12) with a = 24.12(2) A, b = 4.203(3) A, c = 15.67(2) A, β = 98.05(1)°, and Z = 4. The structure is characterized by the covalent three-dimensional network constructed by two types of five-atom-wide Sb57– ribbons that are joined by 6-fold coordinated Mn3+ cations, through which the narrower three-atom-wide Sb35– ribbons are attached as a tag, and interstitial Pr3+ cations and single Sb3– anions locate within the tunnels. Its magnetic susceptibility and isothermal hysteresis suggest ferrimagnetic behavior. The electrical conductivity and Seebeck coefficient of the cold-pressed pellet suggest a semimetal feature that agrees with the spin-polarized calculation results using the tight-binding linear muffin-tin orbital (TB-LMTO) method.
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rb16cd25 39 3 sb36 an electron deficient Zintl Phase containing infinite dodecahedron chains
ChemInform, 2010Co-Authors: Wuzui Zheng, Peng Wang, Yi Liu, Ling ChenAbstract:The new title compound is synthesized by solid state reaction of the elements (Nb tube, 530 °C, 160 h) and characterized by single crystal XRD, electrical and thermal transport measurements, and LAPW electronic structure calculations.
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rb16cd25 39 3 sb36 an electron deficient Zintl Phase containing infinite dodecahedron chains
Inorganic Chemistry, 2010Co-Authors: Wuzui Zheng, Peng Wang, Yi Liu, Ling ChenAbstract:A novel ternary antimonide Rb16Cd25.39(3)Sb36 has been synthesized by a solid-state reaction of the appropriate amount of elements in a welded niobium tube at 530 °C. The compound crystallizes in orthorhombic space group Cmcm (No. 63) with a = 16.499(5) A, b = 12.391(4) A, c = 12.400(4) A, and Z = 1. The structure features a new 3D network constructed of chains of Rb+-centered dodecahedra running along [001]. The atomic distribution of the Cd8Sb12 dodecahedron presents an energetically favored pattern without any Cd−Cd bonding. The formation of the Phase and the occurrence of a very narrow Phase width of Rb16Cd24+xSb36 [0.94(2) ≤ x ≤ 1.47(3)] have been studied in detail. The Fermi level of the title compound is expected to be located between those of the hypothetical models of “[Rb16Cd24Sb36]0” (I, poor metallic) and “[Rb16Cd24Sb36] + 4e” (II, narrow-band-gap semiconductor), which agrees well with the experimental measurements. In the temperature range of 300−473 K, the as-synthesized Rb16Cd25.39(3)Sb36 e...
Mercouri G Kanatzidis - One of the best experts on this subject based on the ideXlab platform.
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synthesis structure and charge transport properties of yb5al2sb6 a Zintl Phase with incomplete electron transfer
Inorganic Chemistry, 2009Co-Authors: Iliya Todorov, Duck Young Chung, Linhui Ye, Arthur J Freeman, Mercouri G KanatzidisAbstract:We report the synthesis, structure, spectroscopic properties, charge and thermal transport, and electronic structure of a new member of the Zintl family, Yb5Al2Sb6. The compound crystallizes in the Ba5Al2Bi6 structure type and requires the addition of Ge or Si in the synthesis, which appears to act as a catalyst. Yb5Al2Sb6 has an anisotropic structure with infinite anionic double chains cross-linked by Yb2+ ions. Polycrystalline ingots of Yb5Al2Sb6 prepared in the presence of 0.5 mol equiv of Ge showed room-temperature conductivity, thermopower, and thermal conductivity of ∼1100 S/cm, ∼20 μV/K, and ∼3.8 W/m·K, respectively. Investigations of other solid solutions of Yb5Al2Sb6, doping effects, and chemical modifications are discussed. Sr only partially replaces Yb in the structure leading to Sr0.85Yb4.15Al2Sb6. Electronic structure calculations performed using a highly precise full-potential linearized augmented plane wave method within the density functional theory scheme show the presence of a negative b...
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a polar and chiral indium telluride featuring supertetrahedral t2 clusters and nonlinear optical second harmonic generation
Chemistry of Materials, 2009Co-Authors: In Chung, Qichun Zhang, Joon I Jang, John B Ketterson, Mercouri G KanatzidisAbstract:The “KIn2” Zintl Phase activates tellurium under solvothermal conditions and yields the compound {[In(en)3][In5Te9(en)2]·0.5en}n (en = ethylenediamine). The material has both a polar and chiral layered framework and exhibits type I Phase-matchable strong second harmonic generation (SHG) response.
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temperature induced abrupt volume inflation in the mixed valence ternary Zintl Phase yb8ge3sb5
Chemical Communications, 2005Co-Authors: Serena Margadonna, Kosmas Prassides, Maria Chondroudi, James R Salvador, Mercouri G KanatzidisAbstract:The Zintl Phase, Yb8Ge3Sb5 exhibits a complex lattice response and an abrupt negative thermal expansion below 15 K – subtle structural changes before and after the transition are consistent with temperature-induced electron transfer from (to) Yb 4f bands to (from) Sb 5p and Ge 4p bands.
Nasrin Kazem - One of the best experts on this subject based on the ideXlab platform.
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Eu11Zn4Sn2As12: A Ferromagnetic Zintl Semiconductor with a Layered Structure Featuring Extended Zn4As6 Sheets and Ethane-like Sn2As6 Units
2018Co-Authors: Kasey P. Devlin, Nasrin Kazem, James C Fettinger, Joya A Cooley, Julia V Zaikina, Jackson R. Badger, Valentin Taufour, Susan M KauzlarichAbstract:We report the synthesis, structure, and magnetic properties of a new Zintl Phase and structure type, Eu11Zn4Sn2As12. The structure and composition of this Phase have been established by single-crystal X-ray diffraction and electron microprobe analysis. Eu11Zn4Sn2As12 crystallizes in monoclinic space group C2/c (No. 15) with the following lattice parameters: a = 7.5679(4) Å, b = 13.0883(6) Å, c = 31.305(2) Å, and β = 94.8444(7)° [R1 = 0.0398; wR2 = 0.0633 (all data)]. The anisotropic structural features staggered ethane-like [Sn2As6]12– units and infinite ∞2[Zn2As3]5– sheets extended in the a–b plane. Eu cations fill the space between these anionic motifs. Temperature-dependent magnetic properties and magnetoresistance of this Zintl Phase have been studied, and the electronic structure and chemical bonding were elucidated using first-principles quantum chemical calculations (TB-LMTO-ASA). Quantum chemical calculations show that the ethane-like units can be considered as consisting of covalent single bonds; however, the ∞2[Zn2As3]5– sheets are best described with delocalized bonding and there is evidence of Eu–As interactions. Temperature-dependent magnetization and transport properties between 2 and 300 K show a ferromagnetic transition at 15 K, a band gap of 0.04 eV, and negative colossal magnetoresistance
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effect of isovalent substitution on the structure and properties of the Zintl Phase solid solution eu7cd4sb8 xasx 2 x 5
ChemInform, 2016Co-Authors: Joya A Cooley, Nasrin Kazem, James C Fettinger, Julia V Zaikina, Susan M KauzlarichAbstract:Eu7Cd4Sb8-xAsx (x = 2, 3, 4, and 5) solid solutions are prepared from the elements in a molten Sn flux (alumina crucible in evacuated silica tubes, 1.
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thermoelectric properties of Zintl antimonides
Handbook on The Physics and Chemistry of Rare Earths, 2016Co-Authors: Nasrin Kazem, Susan M KauzlarichAbstract:Abstract Enhancing the efficiency of thermoelectric devices is critical for their adoption in commercial large-scale applications aimed at converting heat into electricity. To compete with the present mechanical energy generators, thermoelectric materials need to be at least three times more efficient than today's commercial thermoelectrics. This high conversion efficiency corresponds to a thermoelectric figure of merit, zT , of ~ 3, which has remained elusive despite a long history of searching for new thermoelectric materials. The recent discoveries of high zT among Zintl Phase compounds such as Yb 14 MnSb 11 , EuZn 2 Sb 2 , Yb 9 Mn 4.2 Sb 9 , clathrates, and the filled skutterudites show the potential of this class of compounds for more efficient thermoelectric materials. This perspective summarizes the recent progress on Zintl Phases studied for thermoelectric applications with a focus on their chemistry, crystal structure, and transport properties.
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effect of isovalent substitution on the structure and properties of the Zintl Phase solid solution eu7cd4sb8 xasx 2 x 5
Inorganic Chemistry, 2015Co-Authors: Joya A Cooley, Nasrin Kazem, James C Fettinger, Julia V Zaikina, Susan M KauzlarichAbstract:A novel Zintl Phase structure type, Eu7Cd4Sb8–xAsx (x = 2, 3, 4, and 5), with the general formula Eu7Cd4Pn8 (Pn = mixed occupancy Sb and As), was synthesized by molten tin flux reaction. Its structure was determined using single-crystal X-ray diffraction methods. This structure type is only preserved for 2 ≤ x ≤ 5 under our experimental conditions, and efforts to synthesize samples with x 5 resulted in other structure types. The mixed occupancy Sb and As can be thought of as a pseudoatom whose ideal size, in this range of Sb/As ratios, fits the structure. The title Phase crystallizes in the I-centered monoclinic space group I2/m (No. 12, Z = 4) with unit cell parameters ranging as follows: a = 19.7116(17)–19.4546(13) A, b = 4.6751(4)–4.6149(3) A, c = 24.157(2)–23.871(15) A, and β = 95.8798(1)–96.016(5)°, depending on the Sb/As ratio. The structure can be described as parallel double pentagonal tubes resulting from Cd–Pn and Pn–Pn bonding. These double pentagons are formed through corner sharing...
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Effect of Isovalent Substitution on the Structure and Properties of the Zintl Phase Solid Solution Eu7Cd4Sb8–xAsx (2 ≤ x ≤ 5)
2015Co-Authors: Joya Cooley, Nasrin Kazem, James C Fettinger, Julia V Zaikina, Susan M KauzlarichAbstract:A novel Zintl Phase structure type, Eu7Cd4Sb8–xAsx (x = 2, 3, 4, and 5), with the general formula Eu7Cd4Pn8 (Pn = mixed occupancy Sb and As), was synthesized by molten tin flux reaction. Its structure was determined using single-crystal X-ray diffraction methods. This structure type is only preserved for 2 ≤ x ≤ 5 under our experimental conditions, and efforts to synthesize samples with x < 2 or x > 5 resulted in other structure types. The mixed occupancy Sb and As can be thought of as a pseudoatom whose ideal size, in this range of Sb/As ratios, fits the structure. The title Phase crystallizes in the I-centered monoclinic space group I2/m (No. 12, Z = 4) with unit cell parameters ranging as follows: a = 19.7116(17)–19.4546(13) Å, b = 4.6751(4)–4.6149(3) Å, c = 24.157(2)–23.871(15) Å, and β = 95.8798(1)–96.016(5)°, depending on the Sb/As ratio. The structure can be described as parallel double pentagonal tubes resulting from Cd–Pn and Pn–Pn bonding. These double pentagons are formed through corner sharing of the Cd-centered CdPn4 tetrahedra and a Pn–Pn interaction from two adjacent CdPn4 tetrahedra. This structure type is closely related to the Sr11Cd6Sb12 structure type as both share the same bonding features of Pn–Pn bonding and double pentagonal tubes. Electron microprobe analysis confirms the composition of these new Zintl solid solution Phases. The As exhibits preferential substitution on specific sites, and site specificity trends are supported by lowest energy models from theoretical calculations. Theoretical calculations also predict that Sb-rich compounds should be metallic or semimetallic and that they should become more insulating as As content increases. Members of the solid-solution order ferromagnetically between 5 and 6 K and exhibit relatively low electrical resistivity between 50 and 300 K, ranging from ∼0.57 to ∼26 mΩ·cm, increasing with increasing As content
Joya A Cooley - One of the best experts on this subject based on the ideXlab platform.
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high seebeck coefficient and unusually low thermal conductivity near ambient temperatures in layered compound yb2 xeuxcdsb2
Chemistry of Materials, 2018Co-Authors: Joya A Cooley, Phichit Promkhan, Shruba Gangopadhyay, Davide Donadio, W E Pickett, Brenden R Ortiz, Eric S Toberer, Susan M KauzlarichAbstract:Zintl Phases are promising thermoelectric materials because they are composed of both ionic and covalent bonding, which can be independently tuned. An efficient thermoelectric material would have regions of the structure composed of a high-mobility compound semiconductor that provides the “electron–crystal” electronic structure, interwoven (on the atomic scale) with a phonon transport inhibiting structure to act as the “phonon–glass”. The phonon–glass region would benefit from disorder and therefore would be ideal to house dopants without disrupting the electron–crystal region. The solid solution of the Zintl Phase, Yb2–xEuxCdSb2, presents such an optimal structure, and here we characterize its thermoelectric properties above room temperature. Thermoelectric property measurements from 348 to 523 K show high Seebeck values (maximum of ∼269 μV/K at 523 K) with exceptionally low thermal conductivity (minimum ∼0.26 W/m K at 473 K) measured via laser flash analysis. Speed of sound data provide additional suppo...
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Eu11Zn4Sn2As12: A Ferromagnetic Zintl Semiconductor with a Layered Structure Featuring Extended Zn4As6 Sheets and Ethane-like Sn2As6 Units
2018Co-Authors: Kasey P. Devlin, Nasrin Kazem, James C Fettinger, Joya A Cooley, Julia V Zaikina, Jackson R. Badger, Valentin Taufour, Susan M KauzlarichAbstract:We report the synthesis, structure, and magnetic properties of a new Zintl Phase and structure type, Eu11Zn4Sn2As12. The structure and composition of this Phase have been established by single-crystal X-ray diffraction and electron microprobe analysis. Eu11Zn4Sn2As12 crystallizes in monoclinic space group C2/c (No. 15) with the following lattice parameters: a = 7.5679(4) Å, b = 13.0883(6) Å, c = 31.305(2) Å, and β = 94.8444(7)° [R1 = 0.0398; wR2 = 0.0633 (all data)]. The anisotropic structural features staggered ethane-like [Sn2As6]12– units and infinite ∞2[Zn2As3]5– sheets extended in the a–b plane. Eu cations fill the space between these anionic motifs. Temperature-dependent magnetic properties and magnetoresistance of this Zintl Phase have been studied, and the electronic structure and chemical bonding were elucidated using first-principles quantum chemical calculations (TB-LMTO-ASA). Quantum chemical calculations show that the ethane-like units can be considered as consisting of covalent single bonds; however, the ∞2[Zn2As3]5– sheets are best described with delocalized bonding and there is evidence of Eu–As interactions. Temperature-dependent magnetization and transport properties between 2 and 300 K show a ferromagnetic transition at 15 K, a band gap of 0.04 eV, and negative colossal magnetoresistance
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effect of isovalent substitution on the structure and properties of the Zintl Phase solid solution eu7cd4sb8 xasx 2 x 5
ChemInform, 2016Co-Authors: Joya A Cooley, Nasrin Kazem, James C Fettinger, Julia V Zaikina, Susan M KauzlarichAbstract:Eu7Cd4Sb8-xAsx (x = 2, 3, 4, and 5) solid solutions are prepared from the elements in a molten Sn flux (alumina crucible in evacuated silica tubes, 1.
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effect of isovalent substitution on the structure and properties of the Zintl Phase solid solution eu7cd4sb8 xasx 2 x 5
Inorganic Chemistry, 2015Co-Authors: Joya A Cooley, Nasrin Kazem, James C Fettinger, Julia V Zaikina, Susan M KauzlarichAbstract:A novel Zintl Phase structure type, Eu7Cd4Sb8–xAsx (x = 2, 3, 4, and 5), with the general formula Eu7Cd4Pn8 (Pn = mixed occupancy Sb and As), was synthesized by molten tin flux reaction. Its structure was determined using single-crystal X-ray diffraction methods. This structure type is only preserved for 2 ≤ x ≤ 5 under our experimental conditions, and efforts to synthesize samples with x 5 resulted in other structure types. The mixed occupancy Sb and As can be thought of as a pseudoatom whose ideal size, in this range of Sb/As ratios, fits the structure. The title Phase crystallizes in the I-centered monoclinic space group I2/m (No. 12, Z = 4) with unit cell parameters ranging as follows: a = 19.7116(17)–19.4546(13) A, b = 4.6751(4)–4.6149(3) A, c = 24.157(2)–23.871(15) A, and β = 95.8798(1)–96.016(5)°, depending on the Sb/As ratio. The structure can be described as parallel double pentagonal tubes resulting from Cd–Pn and Pn–Pn bonding. These double pentagons are formed through corner sharing...
