Zinc-deficiency in intermetallics with the NaZn13 type

Saparov, Bayrammurad; Bobev, Svilen

doi:10.1016/j.jallcom.2007.09.040

Cited by 10 publications

(11 citation statements)

References 19 publications

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“…Refinement of the models against the neutron data obtained for each analogue, which yield excellent statistics, were not prone to local minima, and reproduced the EDS compositions without a large number of restraints or parameters, considered an 8 b Wyckoff site with only occupationally disordered Cu and substitutional disorder of Cu, Al, and Ga on the 96 i Wyckoff site. This final model is very similar to the models reported for other compounds adopting the NaZn 13 structure-type as described by Bobev . Additionally, an arc-melted button of Eu(Cu,Al) 13– x was prepared to compare its magnetic properties to those of Eu(Cu,Al) 13– x .…”

Section: Discussionsupporting

confidence: 69%

“…Furthermore, a recent reinvestigation of EuZn 13– x shows that this structurally related phase is not fully stoichiometric, and the true composition is approximately EuZn 12.75 . The Zn at the center of the icosahedron (8 b ) is partially occupied, whereas the Zn atoms (96 i ) at the corners of the icosahedron are fully occupied . It was concluded that the partial occupancy helps the material reach the optimal number of valence electrons as discussed in detail by Nordell and Miller …”

Section: Resultsmentioning

confidence: 93%

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Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)_13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)_13–x

Phelan¹,

Kangas²,

McCandless³

et al. 2012

Inorg. Chem.

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Ln(Cu,Al,Ga)(13-x) (Ln = La-Pr, and Eu; x ~ 0.2) were synthesized by a combined Al/Ga flux. Single crystal X-ray and neutron diffraction experiments revealed that these compounds crystallize in the NaZn(13) structure-type (space group Fm3[overline]c) with lattice parameters of a ~ 12 Å, V ~ 1600 Å, and Z ~ 8. Our final neutron models led us to conclude that Cu is occupationally disordered on the 8b Wyckoff site while Cu, Al, and Ga are substitutionally disordered on the 96i Wyckoff site of this well-known structure-type. The magnetic susceptibility data show that Ce(Cu,Al,Ga)(13-x) and Pr(Cu,Al,Ga)(13-x) exhibit paramagnetic behavior down to the lowest temperatures measured while Eu(Cu,Al,Ga)(13-x) displays ferromagnetic behavior below 6 K. Eu(Cu,Al)(13-x) was prepared via arc-melting and orders ferromagnetically below 8 K. The magnetocaloric properties of Eu(Cu,Al,Ga)(13-x) and Eu(Cu,Al)(13-x) were measured and compared. Additionally, an enhanced value of the Sommerfeld coefficient (γ = 356 mJ/mol-K(2)) was determined for Pr(Cu,Al,Ga)(13-x). Herein, we present the synthesis, structural refinement details, and physical properties of Ln(Cu,Al,Ga)(13-x) (Ln = La-Pr, and Eu) and Eu(Cu,Al)(13-x).

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Section: Discussionsupporting

confidence: 69%

Section: Resultsmentioning

confidence: 93%

Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)_13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)_13–x

Phelan¹,

Kangas²,

McCandless³

et al. 2012

Inorg. Chem.

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“…The unit cells of these tetragonal variants are 1/√2 × 1/√2 × 1 of the parent cubic‐type. It should also be noted that within cubic and tetragonal types several examples exhibit partial (SrAu 5.96 Al 6.34 , EuCu 2.6 Ga 10.2 , CaZn 12.9 , SrZn 12.9 , and EuZn 12.8 30–33) or zero (BaZn 10.1 Al 1.9 34) occupation of the icosahedral centers. Included among orthorhombic modifications are LaNi 7.4 In 5.6 , SrNi 7.9 In 5.1 , and SrCu 7 In 6 35–37.…”

Section: Resultsmentioning

confidence: 99%

Complex Polyanionic Nets in RbAu_4.01(2)Ga_8.64(5) and CsAu₅Ga₉: The Role of Cations in the Formation of New Polar Intermetallics

Smetana

Corbett

Miller

2014

Zeitschrift anorg allge chemie

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“…The structures of a few other compounds can also be depicted as disordered superstructures of the NaZn 13 -type, i.e., RbAu 4.0 Ga 8.7 , Cs 1.4 Zn 16 , and ∼BaAu 4 Ga 8 (Table ). These compositions indicate that not all compounds adopt a fixed 1:13 atom ratio but are rather distributed between 1:12 and 1:13, depending on the occupations of the icosahedral centers for both the binary and ternary representatives. ,− …”

Section: Introductionmentioning

confidence: 99%

Cation-Poor Complex Metallic Alloys in Ba(Eu)–Au–Al(Ga) Systems: Identifying the Keys that Control Structural Arrangements and Atom Distributions at the Atomic Level

Smetana¹,

Steinberg²,

Mudryk³

et al. 2015

Inorg. Chem.

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Four complex intermetallic compounds BaAu(6±x)Ga(6±y) (x = 1, y = 0.9) (I), BaAu(6±x)Al(6±y) (x = 0.9, y = 0.6) (II), EuAu6.2Ga5.8 (III), and EuAu6.1Al5.9 (IV) have been synthesized, and their structures and homogeneity ranges have been determined by single crystal and powder X-ray diffraction. Whereas I and II originate from the NaZn13-type structure (cF104-112, Fm3̅c), III (tP52, P4/nbm) is derived from the tetragonal Ce2Ni17Si9-type, and IV (oP104, Pbcm) crystallizes in a new orthorhombic structure type. Both I and II feature formally anionic networks with completely mixed site occupation by Au and triel (Tr = Al, Ga) atoms, while a successive decrease of local symmetry from the parental structures of I and II to III and, ultimately, to IV correlates with increasing separation of Au and Tr on individual crystallographic sites. Density functional theory-based calculations were employed to determine the crystallographic site preferences of Au and the respective triel element to elucidate reasons for the atom distribution ("coloring scheme"). Chemical bonding analyses for two different "EuAu6Tr6" models reveal maximization of the number of heteroatomic Au-Tr bonds as the driving force for atom organization. The Fermi levels fall in broad pseudogaps for both models allowing some electronic flexibility. Spin-polarized band structure calculations on the "EuAu6Tr6" models hint to singlet ground states for europium and long-range magnetic coupling for both EuAu6.2Ga5.8 (III) and EuAu6.1Al5.9 (IV). This is substantiated by experimental evidence because both compounds show nearly identical magnetic behavior with ferromagnetic transitions at TC = 6 K and net magnetic moments of 7.35 μB/f.u. at 2 K. The effective moments of 8.3 μB/f.u., determined from Curie-Weiss fits, point to divalent oxidation states for europium in both III and IV.

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Zinc-deficiency in intermetallics with the NaZn13 type

Cited by 10 publications

References 19 publications

Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)_13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)_13–x

Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)_13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)_13–x

Complex Polyanionic Nets in RbAu_4.01(2)Ga_8.64(5) and CsAu₅Ga₉: The Role of Cations in the Formation of New Polar Intermetallics

Cation-Poor Complex Metallic Alloys in Ba(Eu)–Au–Al(Ga) Systems: Identifying the Keys that Control Structural Arrangements and Atom Distributions at the Atomic Level

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Zinc-deficiency in intermetallics with the NaZn13 type

Cited by 10 publications

References 19 publications

Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)13–x

Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)13–x

Complex Polyanionic Nets in RbAu4.01(2)Ga8.64(5) and CsAu5Ga9: The Role of Cations in the Formation of New Polar Intermetallics

Cation-Poor Complex Metallic Alloys in Ba(Eu)–Au–Al(Ga) Systems: Identifying the Keys that Control Structural Arrangements and Atom Distributions at the Atomic Level

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Product

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About

Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)_13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)_13–x

Synthesis, Structure, and Physical Properties of Ln(Cu,Al,Ga)_13–x (Ln = La–Pr, and Eu) and Eu(Cu,Al)_13–x

Complex Polyanionic Nets in RbAu_4.01(2)Ga_8.64(5) and CsAu₅Ga₉: The Role of Cations in the Formation of New Polar Intermetallics