| 1. |
- Babizhetskyy, Volodymyr, et al.
(author)
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New cation-disordered quaternary selenides Tl(2)Ga(2)TtSe(6) (Tt = Ge, Sn)
- 2020
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In: Zeitschrift für Naturforschung. B, A journal of chemical sciences. - : Walter de Gruyter GmbH. - 0932-0776 .- 1865-7117. ; 75:1-2, s. 135-142
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Journal article (peer-reviewed)abstract
- Two new quaternary selenides of the alpha-TlSe structure type have been synthesized and characterized. Single crystal X-ray diffraction analysis has revealed that Tl2Ga2SnSe6 crystallizes with space group I4/mmc, a =8.095(1), c=6.402(1) angstrom, with a refined composition of Tl1-xGa1-ySny Se-2 (x= y=0.345(5)), Z=4, R1=0.028; wR2= 0.066. The crystal structure of the isostructural compound Tl2Ga2GeSe6 has been determined by means of powder X-ray diffraction: space group I4/mmc, Z= 4, a= 8.0770(4 ), c= 6.2572(5) angstrom, refined composition Tl1-xGa1-ySny Se-2, x=0343(5), y=0.35(2), (R-B(I) = 0.084; R-p = 0.041; R-PW= 0.058). According to their optical absorption spectra all compounds are semiconductors with relatively narrow direct band gaps of 2.15(3) and 2.05(5) eV for the Ge and Sn phase, respectively.
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| 2. |
- Babizhetskyy, Volodymyr, et al.
(author)
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New intermetallics R1+xZr1−xNi (R = Er–Tm, x ~ 0.5) with the TiNiSi type of structure
- 2021
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In: Intermetallics (Barking). - : Elsevier BV. - 0966-9795 .- 1879-0216. ; 137
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Journal article (peer-reviewed)abstract
- A new series of isostructural rare earth compounds R1+xZr1−xNi (R = Er, Tm, Lu; x ~ 0.5) was synthesized from the elements by arc melting and subsequent annealing at 870 K for 1400 h. The crystal structures of the intermetallic compounds were investigated by means of single-crystal X-ray diffraction. They all crystallize in the TiNiSi structure type (space group Pnma, No. 62, oP12). In R1+xZr1−xNi, the R/Zr statistical mixture leading to nonequiatomic compositions occupies the position corresponding to the nickel site of the TiNiSi structure type. The calculated shortest interatomic distances are close to the sums of the single-bond covalent radii of respective elements. Electronic structure calculations performed with the tight-binding LMTO method revealed the non-zero density of states at the Fermi level and suggest metallic character. R1+xZr1−xNi (R = Er, Tm, Lu; x ~ 0.5) undergoes no long-range magnetic ordering down to 2 K.
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| 3. |
- Babizhetskyy, Volodymyr, et al.
(author)
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Crystal and electronic structures of the new ternary gallide Zr12Pd40−xGa31+y (x = 0–1.5, y = 0–0.5)
- 2023
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In: Journal of Solid State Chemistry. - 0022-4596 .- 1095-726X. ; 327
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Journal article (peer-reviewed)abstract
- Zr12Pd40Ga31 was prepared from the elements by arc melting under argon and subsequent annealing at 870 K for 720 h. Single-crystal X-ray diffraction reveals that Zr12Pd40Ga31 crystallizes in a new hexagonal structure type: Pearson symbol (PS) hP166, space group P6/mmm, a = 18.7670(6) Ǻ, c = 8.6634(6) Ǻ). The crystal structure consists of three types of atomic layers – two flat sheets at z = 0 (layer A) and z = 0.5 (C) and one corrugated at z = 0.25 and z = 0.75 (B), which stack in the sequence … ABCB … along the [001] direction. The structure shows close vicinity to a series of hexagonal structures with PS hP164–hP171. These compounds show peculiar structural variability expressed in the different atomic occupations of the Wyckoff positions along and around the 3-fold and 6-fold axes. Homogeneity range and lattice parameters of new ternary compound Zr12Pd40−xGa31+y (x = 0–1.5, y = 0–0.5) have been refined from EDX and powder XRD data. Electronic structure calculations and bonding analysis have been performed for an idealized model revealing domination of the Pd–Ga and Ga–Ga interactions.
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| 4. |
- Kotur, Bogdan, et al.
(author)
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Crystal and electronic structures of a new hexagonal silicide Sc38Co144Si97
- 2022
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In: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 316
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Journal article (peer-reviewed)abstract
- Sc38Co144Si97 was prepared from the elements by arc melting under argon and subsequent annealing at 800 °C for 350 h. Single-crystal X-ray diffraction reveals Sc38Co144Si97 to crystallize in a new hexagonal structure type: Pearson's symbol hP279, space group P63/m, a = 33.624(7), c = 3.639(1) Å. The crystal structure of Sc38Co144Si97 can be considered as a 2D intergrowth of three kinds of fragments of simpler structure types: hexagons and quadrilaterals with the arrangements of the Sc6Co30Si19-type and triangles with the arrangement of the Gd4Co13(Si, P)9-type. Quantum chemical calculations have been performed to analyze the electronic structure and provide deeper insight into the structure-property relationships. The Extended Hückel (EH) calculation indicates that Co in Sc38Co144Si97 adopts close to a d10 configuration owing to the covalent interaction with Si. The Sc–Co and Sc–Si interactions are more ionic, and Co–Co and Co–Si bonds are more covalent interactions.
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| 5. |
- Babizhetskyy, V., et al.
(author)
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Investigation in the ternary Ta-Ni-P system : Solid state phase equilibria at T=1070 K, crystal and electronic structures of new ternary phosphides
- 2021
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In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 864
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Journal article (peer-reviewed)abstract
- The solid state phase diagram for the ternary Ta-Ni-P system was established at T=1070 K in the region of up to 67 at% of P by means of X-ray powder diffraction methods (PXRD). Six ternary compounds, namely Ta4NiP (Nb4CoSi-type), Ta1.10-0.82Ni0.90-1.18P (TiNiSi-type), TaNiP2 (NbNiP2-type), Ta(5.00-4.81)Ni(4.00-4.19)P4 (Nb5Cu4Si4-type), TaNi2P (own structure type) and Ta1-0.08(1)Ni0.08(1)P2 (OsGe2-type) have been confirmed to exist. Rather minor Ta/Ni homogeneity ranges have been found for alpha-Ta3-xNixP (x=0.2) (Ti3P-type), Ta1-xNixP (x=0.18) (NbAs-type), Ni3-xTaxP (x=0.2) (Ni3P-type) and Ni2-xTaxP (x=0.25) (Fe2P-type). The crystal structure of Ta4.811(9)Ni4.189(9)P4 has been refined from single crystal X-ray diffraction data (Nb5Cu4Si4-type, space group I4/m, a =9.8474(17), c=3.5182(7) angstrom, R1=0.0283, wR2=0.0470), while that of the new TaNi2P compound was determined by means of PXRD. This phosphide crystalizes in its own structure type (space group Pnma, a=8.3588(3), b=3.5208(1), c=6.7051(3) angstrom, R-I=0.044, R-P=0.161). A new isostructural Fe-compound, TaFe2P (a=8.358(2), b=3.5194(7), c=6.703(1) angstrom), was also synthetized. The electronic structures of Ta5Ni4P4 and TaNi2P were analyzed using the tight-binding linear muffin-tin orbital (TB-LMTO) and extended Huckel methods.
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| 6. |
- Kotur, B., et al.
(author)
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Crystal and electronic structures of the new ternary silicide Sc12Co41.8Si30.2
- 2021
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In: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 302
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Journal article (peer-reviewed)abstract
- Sc12Co41.8Si30.2 was prepared from the elements by arc melting under argon and subsequent tempering at 800 °C for 350 h. Single-crystal X-ray diffraction reveals Sc12Co41.8Si30.2 to crystallize in a new hexagonal structure type: Pearson's symbol (PS) hP168, space group P6/mmm, a = 17.291(1), c = 8.0293(8) Å. The crystal structure is formed of three types of atomic layers along the [001] direction – two flat at z = 0 and z = 0.5 and one corrugated at z = 0.16–0.33 and z = 0.67–0.84, shows a substantial degree of positional and occupational disorder and close structural relationships to a series of hexagonal structures with PS hP164–hP171. Quantum chemical calculations have been performed to analyze the electronic structure and provide deeper insight into the structure-property relationships. The quantum chemical calculation indicates that the material features both two-center, two-electron localized bonding and multi-center multi-electron delocalized bonding.
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