Oksana Sologub - Academia.edu (original) (raw)
Papers by Oksana Sologub
Solid State Communications, 2003
Journal of Solid State Chemistry, 2011
ABSTRACT The isothermal section for the system Ce–Zn–B has been established at 800 °C using elect... more ABSTRACT The isothermal section for the system Ce–Zn–B has been established at 800 °C using electron microprobe analysis and X-ray powder diffraction. No ternary compounds exist and mutual solid solubilities of binary phases are negligible. In the concentration range of 10.0–10.5 at% Ce two structural modifications have been confirmed: high temperature βCe2Zn17 above ∼750 °C with the Th2Zn17 type (R3̄m, a=0.90916(4) nm, c=1.3286(1) nm) and low temperature αCeZn7 (Ce1−xZn5+2x; x∼0.33) up to 750 °C for which we attributed the TbCu7 type (P6/mmm, a=0.52424(2), c=0.44274(1) nm). The crystal structure of CeZn7 was derived from the Rietveld refinement of X-ray powder intensities. Precise data on atom site distribution and positional parameters have been furthermore provided from X-ray single crystal refinements for two compounds, for which crystal structures hitherto have only been derived from X-ray diffraction photographs: Ce3Zn11 (Immm, a=0.45242(2) nm, b=0.88942(3) nm, c=1.34754(4) nm) and Ce3Zn22 (I41/amd; a=0.89363(2) nm, c=2.1804(5) nm).
Journal of Physics: Condensed Matter, 2009
Novel ternary compounds, M(2)Pd(14+x)B(5-y) (M = La, Ce, Pr, Nd, Sm, Eu, Gd, Lu, Th; x∼0.9, y∼0.... more Novel ternary compounds, M(2)Pd(14+x)B(5-y) (M = La, Ce, Pr, Nd, Sm, Eu, Gd, Lu, Th; x∼0.9, y∼0.1), have been synthesized by arc melting. The crystal structures of Nd(2)Pd(14+x)B(5-y) and Th(2)Pd(14+x)B(5-y) were determined from x-ray single-crystal data and both are closely related to the structure type of Sc(4)Ni(29)B(10). All compounds were characterized by Rietveld analyses and found to be isotypic with the Nd(2)Pd(14+x)B(5-y) type. Measurements of the temperature dependent susceptibility and specific heat as well as the temperature and field dependent resistivity were employed to derive basic information on bulk properties of these compounds. The electrical resistivity of M(2)Pd(14+x)B(5-y), in general, is characterized by small RRR (residual resistance ratio) values originating from defects inherent to the crystal structure. Whereas the compounds based on Ce, Nd, Sm and Gd exhibit magnetic order, those based on Pr and Eu seem to be non-magnetic, at least down to 400 mK. While the non-magnetic ground state of the Pr based compound is a consequence of crystalline electric field effects in the context of the non-Kramers ion Pr, the lack of magnetic order in the case of the Eu based compound results from an intermediate valence state of the Eu ion.
Journal of Physics: Condensed Matter, 2010
Phase equilibria in the system U-Pd-B were established at 850 °C by light optical microscopy (LOM... more Phase equilibria in the system U-Pd-B were established at 850 °C by light optical microscopy (LOM) and x-ray powder and single crystal diffraction. Whereas in as-cast alloys only one ternary compound, τ(1)-U(2 + x)Pd(21 - x)B(6), was found to form at x ∼ 0.5, a further compound τ(2) with hitherto unknown structure was observed in alloys annealed at 850 °C. Due to the formation of suitable single crystals, the crystal structures of two binary compounds, UB(12) and UPd(3) have been redetermined from high precision x-ray data. Similarly, the crystal structure of τ(1)-U(2.5)Pd(20.5)B(6) was investigated by single crystal x-ray diffraction (XRD) revealing isotypism with the Cr(23)C(6)-type, (space group [Formula: see text]; a = 1.1687(5) nm; R(F)(2) = Σ|F(0)(2) - F(c)(2)|/ΣF(0)(2) = 0.021). τ(1)-U(2 + x)Pd(21 - x)B(6) is a partially ordered compound where 0.37(1)U + 0.63Pd atoms randomly share the 4a site in (0, 0, 0). Whereas mutual solubility of U-borides and Pd-borides was found at 850 °C to be below 1.0 at.%, a large homogeneity region of fcc-Pd(U, B) extends into the ternary system. U(2.5)Pd(20.5)B(6) has metallic behavior; the ground state properties are determined from a balance of the Kondo effect and the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, revealing long range antiferromagnetic ordering below 6 K. An extraordinarily large Sommerfeld value (γ > 500 mJ mol(-1) K(-2)) groups U(2.5)Pd(20.5)B(6) among heavy fermion materials.
Journal of Alloys and Compounds, 1996
Phase equilibria in the ternary systems NdRu(Os)Si have been established in an isothermal secti... more Phase equilibria in the ternary systems NdRu(Os)Si have been established in an isothermal section at 870 K; eight ternary silicides of neodymium have been observed.
Journal of Alloys and Compounds, 2001
Dy Co Sn , a new structure type of ternary intermetallic stannides 117 57 112 with a giant unit c... more Dy Co Sn , a new structure type of ternary intermetallic stannides 117 57 112 with a giant unit cell a,c , b c a b
Journal of Alloys and Compounds, 2001
Phase equilibria were established in the Y-Fe-Al ternary system within the concentration region 5... more Phase equilibria were established in the Y-Fe-Al ternary system within the concentration region 50-100 at.% Al for an isothermal section at 1070 K by means of scanning electron microscopy and powder X-ray diffraction. Two ternary aluminides were observed,Y Fe Al (4#x#5.6) with the ThMn-type structure, a58.6467(9)-8.7604(7) A, c55.0374(6)-5.0504(5) A and YFe Al , x 122x 12 2 10˚Y bFe Al-type structure, a58.9649(6) A, b510.1568(6) A, c59.0113(6) A. The only binary which forms a prolonged solid solution 2 10r ange is YAl. The unit cell edge of the YFe Al compounds, MgCu-type structure, decreases with Fe content from 7.834(9) A for 2 x 22x 2 57ẍ 50 down to 7.689(4) A for x50.5. Fe Mossbauer spectroscopy data of YFe Al show an unusually large isomer shift for Fe in 2 10 Al-containing intermetallics and confirm that no magnetic ordering occurs down to 5 K.
Journal of Alloys and Compounds
Abstract In this work we report the results of our investigation of YbB66 as a potential high-tem... more Abstract In this work we report the results of our investigation of YbB66 as a potential high-temperature thermoelectric material. A high-quality single crystal has been grown by the optical floating zone method. Thermoelectric transport properties were measured in a temperature range of 373–973 K YbB66, like REB66 compounds in general, is a p-type semiconductor whose electrical properties can be described by Mott's variable range hopping mechanism. It shows very large Seebeck coefficient ranging from 588 μV K−1 at 373 K to 241 μV K−1 at 973 K and an electrical resistivity ρ that decreases by almost 4 orders of magnitude from 9.4×10−1 Ω m to 2.4 × 10−4 Ω m. Together with the low thermal conductivity of 2.6 W m−1 K−1 a maximum ZT close to 0.1 around 1000 K was determined with trend of sharp increase toward higher temperatures, which is similar to the previous report of SmB66, and significantly larger than previously reported for Y and Er phases of REB66. However, unlike SmB66, the effective magnetic moment suggests a trivalent state for Yb instead of mixed valence, which was determined by measuring the magnetic susceptibility from 2 to 300 K. The composition of YbB66 was indicated to be metal-rich, which actually may be the origin of the good performance.
ChemInform
Structure D 2000 Rietveld Refinement of the LnNi4B Compounds (Ln: Gd, Tb, Er).-The structure of t... more Structure D 2000 Rietveld Refinement of the LnNi4B Compounds (Ln: Gd, Tb, Er).-The structure of the title compounds annealed at 1070 K is determined by Rietveld refinement of powder XRD data. All the compounds crystallize with a CeCo4B-type structure in the hexagonal space group P6/mmm with Z = 2. The results disagree with crystal structure investigations of LnNi4B compounds reported previously, which could be an indication of strong dependence of structure formation on the temperature as well as on the nature of the rare earth metal.
Acta Materialia
The doping effect of zirconium on the structure, Seebeck coefficient and electrical resistivity o... more The doping effect of zirconium on the structure, Seebeck coefficient and electrical resistivity of β-rhombohedral B was studied for the metal rich concentration range Zr x B 100-x , 1.88≤x≤2.75. Structural studies proved the Zr atoms mainly in E and D voids for the metal rich compositions, and also elucidated the minor Zr occupancies of the N, F and A 1 holes. Seebeck coefficients were effectively shifted within a wide range of positive and negative values by varying the Zr content (p-type: S max ~ +420 µVK-1 at 673 K for x=1.88; n-type: S max ~-670 µVK-1 at 473 K for x=2.74). Electrical resistivities generally followed the Mott's relation for the variable-range hopping. Excellent compositional agreement has been observed between structural and thermoelectric properties discontinuities.
Inorganic Chemistry
Two borides, ScRu 2 B 3 and Sc 2 RuB 6 were obtained by argon-arc melting of the elements followe... more Two borides, ScRu 2 B 3 and Sc 2 RuB 6 were obtained by argon-arc melting of the elements followed by annealing at 800 ºC. ScRu 2 B 3 exhibits a new structure type with the space group Cmcm (a=3.0195(2) Å, b=15.4056(8) Å, c=5.4492(3) Å; single crystal X-ray data; R F 2 =0.0105). Sc 2 RuB 6 adopts the Y 2 ReB 6-type structure (space group Pbam; a=8.8545(2) Å, b=11.1620(3) Å, c=3.4760(1) Å; single crystal X-ray data; R F 2 =0.0185). ScRu 2 B 3 displays an unusual intergrowth of CeCo 3 B 2-and AlB 2-related slabs; a striking feature is a boat configuration of puckered boron hexagons within infinite B6 3 nets. Sc 2 RuB 6 presents twodimensional planar nets of condensed boron pentagons, hexagons and heptagons sandwiched between metal layers. In Sc/Y substituted Y 2 ReB 6-type, Y atoms are distributed exclusively inside the boron heptagons. Exploration of the Sc-RuB system at 800 ºC including binary boundaries employing EPMA and powder X-ray diffraction technique furthermore rules out the existence of previously reported "ScRuB 4 " but confirms the formation and crystal structure of Sc 2 Ru 5 B 4. ScRu 4 B 4 forms in cast alloys (LuRu 4 B 4-type structure; space group I4 1 /acd (no. 142), a=7.3543(2) Å, c=14.92137(8) Å). Cell parameters and atomic coordinates have been refined for ScRu 2 B 3 , Sc 2 RuB 6 and ScRu 4 B 4 in the scope of generalized gradient approximation. Ab initio electronic structure calculations indicate a moderate electronic density of states at the Fermi level situated near the upper edge of essentially filled d-bands. Electrical resistivity measurements characterize ScRu 2 B 3 and Sc 2 RuB 6 as metals in concord with electronic band structure calculations.
Journal of Alloys and Compounds
A new Pt-doped yttrium boride of the YB 50 family, YB 45-x Pt y , x=2.12, y=0.21 (space group Pba... more A new Pt-doped yttrium boride of the YB 50 family, YB 45-x Pt y , x=2.12, y=0.21 (space group Pbam, a=16.6246(4) Å, b=17.6453(4) Å, c=9.4167(2) Å), has been synthesized by arcmelting pure elements and subsequent annealing at 1123 K. A single crystal has been studied in order to assess the Pt-doping effect on the crystal structure. Insertion of Pt in two 4h interstitial sites of the boron atom framework leads to the transformation of-[B 12 ]-[B 12 ]icosahedral chain into-[B 11 ]-Pt-[B 11 ]-for 38.6% of them as well as, to a lesser extent, induces the disorder into the [B 15 ] polyhedron and neighboring interstitial B site (97.3% vs 2.7%).
Journal of Solid State Chemistry
Two boron rich phases were successfully synthesized by borothermal reduction of Yb oxide under va... more Two boron rich phases were successfully synthesized by borothermal reduction of Yb oxide under vacuum. For the new boron-poorer phase, the single phase was established at around [B]/[Yb]=43.3 at 1500 °C (Pbam space group; YB 50-type; a=16.5811(5) Å, b=17.5950(5) Å, c=9.4647(3) Å; powder X-ray diffraction; Rietveld refinement). The crystal structure of the boron-richer phase ([B]/[Yb]=56.0) has been elucidated by single crystal X-ray diffraction (3 Fm c space group; YB 66-type; a=23.3587(6) Å). Powder X-ray diffraction data of the alloy YbB~7 0 annealed at 1825 °C yielded, along with the YB 66-type compound (a=23.3691(2) Å), β-rh B as a secondary phase (m R3 space group, a=10.9298(3) Å, c=23.875(1) Å), for which the solubility of Yb was found to be below 1 at.%. Both YbB 43.3 and YbB 56.0 feature complicated boron atom frameworks which exhibit shorter B-B separations both within and between boron clusters as compared to those observed for prototype structures.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 6, 2017
A new member of the series of Th7 Fe3 -type derivative structures, h-(Pd0.86 Cu0.14 )7 B3 (≡Pd6.0... more A new member of the series of Th7 Fe3 -type derivative structures, h-(Pd0.86 Cu0.14 )7 B3 (≡Pd6.02 Cu0.98 B3 , unique structure type Pd6 CuB3 , space group P63 cm, a=12.9426(9) Å, c=4.8697(4) Å, single-crystal X-ray diffraction (XRD) data) was obtained from as cast alloys and alloys annealed at 600-650 °C. Further substitution of Cu by Pd led to formation of a Mn7 C3 -type structure, o-(Pd0.93 Cu0.07 )7 B3 (≡Pd6.51 Cu0.49 B3 , space group Pnma, a=4.8971(2) Å, b=7.5353(3) Å, c=12.9743(6) Å, single-crystal XRD). Isotypic LT h-(Pt0.70 Cu0.30 )7 B3 (≡Pt4.90 Cu2.10 B3 ) was observed in the Pt-Cu-B system as a low-temperature (LT) phase (T≤600 °C) (powder XRD), whereas the Th7 Fe3 -type (high-temperature (HT) h-(Pt0.73 Cu0.27 )7 B3 ≡Pt5.11 Cu1.89 B3 , space group P63 mc, a=7.4671(1) Å, c=4.9039(1) Å, powder XRD) proved to be stable at high temperature. The three structures are built of columns of face connected metal octahedra and columns of metal tetrahedra alternatingly fused by common ...
Russian Journal of Inorganic Chemistry, 1991
J Phys Condens Matter, 2002
Solid State Communications, 2003
Journal of Solid State Chemistry, 2011
ABSTRACT The isothermal section for the system Ce–Zn–B has been established at 800 °C using elect... more ABSTRACT The isothermal section for the system Ce–Zn–B has been established at 800 °C using electron microprobe analysis and X-ray powder diffraction. No ternary compounds exist and mutual solid solubilities of binary phases are negligible. In the concentration range of 10.0–10.5 at% Ce two structural modifications have been confirmed: high temperature βCe2Zn17 above ∼750 °C with the Th2Zn17 type (R3̄m, a=0.90916(4) nm, c=1.3286(1) nm) and low temperature αCeZn7 (Ce1−xZn5+2x; x∼0.33) up to 750 °C for which we attributed the TbCu7 type (P6/mmm, a=0.52424(2), c=0.44274(1) nm). The crystal structure of CeZn7 was derived from the Rietveld refinement of X-ray powder intensities. Precise data on atom site distribution and positional parameters have been furthermore provided from X-ray single crystal refinements for two compounds, for which crystal structures hitherto have only been derived from X-ray diffraction photographs: Ce3Zn11 (Immm, a=0.45242(2) nm, b=0.88942(3) nm, c=1.34754(4) nm) and Ce3Zn22 (I41/amd; a=0.89363(2) nm, c=2.1804(5) nm).
Journal of Physics: Condensed Matter, 2009
Novel ternary compounds, M(2)Pd(14+x)B(5-y) (M = La, Ce, Pr, Nd, Sm, Eu, Gd, Lu, Th; x∼0.9, y∼0.... more Novel ternary compounds, M(2)Pd(14+x)B(5-y) (M = La, Ce, Pr, Nd, Sm, Eu, Gd, Lu, Th; x∼0.9, y∼0.1), have been synthesized by arc melting. The crystal structures of Nd(2)Pd(14+x)B(5-y) and Th(2)Pd(14+x)B(5-y) were determined from x-ray single-crystal data and both are closely related to the structure type of Sc(4)Ni(29)B(10). All compounds were characterized by Rietveld analyses and found to be isotypic with the Nd(2)Pd(14+x)B(5-y) type. Measurements of the temperature dependent susceptibility and specific heat as well as the temperature and field dependent resistivity were employed to derive basic information on bulk properties of these compounds. The electrical resistivity of M(2)Pd(14+x)B(5-y), in general, is characterized by small RRR (residual resistance ratio) values originating from defects inherent to the crystal structure. Whereas the compounds based on Ce, Nd, Sm and Gd exhibit magnetic order, those based on Pr and Eu seem to be non-magnetic, at least down to 400 mK. While the non-magnetic ground state of the Pr based compound is a consequence of crystalline electric field effects in the context of the non-Kramers ion Pr, the lack of magnetic order in the case of the Eu based compound results from an intermediate valence state of the Eu ion.
Journal of Physics: Condensed Matter, 2010
Phase equilibria in the system U-Pd-B were established at 850 °C by light optical microscopy (LOM... more Phase equilibria in the system U-Pd-B were established at 850 °C by light optical microscopy (LOM) and x-ray powder and single crystal diffraction. Whereas in as-cast alloys only one ternary compound, τ(1)-U(2 + x)Pd(21 - x)B(6), was found to form at x ∼ 0.5, a further compound τ(2) with hitherto unknown structure was observed in alloys annealed at 850 °C. Due to the formation of suitable single crystals, the crystal structures of two binary compounds, UB(12) and UPd(3) have been redetermined from high precision x-ray data. Similarly, the crystal structure of τ(1)-U(2.5)Pd(20.5)B(6) was investigated by single crystal x-ray diffraction (XRD) revealing isotypism with the Cr(23)C(6)-type, (space group [Formula: see text]; a = 1.1687(5) nm; R(F)(2) = Σ|F(0)(2) - F(c)(2)|/ΣF(0)(2) = 0.021). τ(1)-U(2 + x)Pd(21 - x)B(6) is a partially ordered compound where 0.37(1)U + 0.63Pd atoms randomly share the 4a site in (0, 0, 0). Whereas mutual solubility of U-borides and Pd-borides was found at 850 °C to be below 1.0 at.%, a large homogeneity region of fcc-Pd(U, B) extends into the ternary system. U(2.5)Pd(20.5)B(6) has metallic behavior; the ground state properties are determined from a balance of the Kondo effect and the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, revealing long range antiferromagnetic ordering below 6 K. An extraordinarily large Sommerfeld value (γ > 500 mJ mol(-1) K(-2)) groups U(2.5)Pd(20.5)B(6) among heavy fermion materials.
Journal of Alloys and Compounds, 1996
Phase equilibria in the ternary systems NdRu(Os)Si have been established in an isothermal secti... more Phase equilibria in the ternary systems NdRu(Os)Si have been established in an isothermal section at 870 K; eight ternary silicides of neodymium have been observed.
Journal of Alloys and Compounds, 2001
Dy Co Sn , a new structure type of ternary intermetallic stannides 117 57 112 with a giant unit c... more Dy Co Sn , a new structure type of ternary intermetallic stannides 117 57 112 with a giant unit cell a,c , b c a b
Journal of Alloys and Compounds, 2001
Phase equilibria were established in the Y-Fe-Al ternary system within the concentration region 5... more Phase equilibria were established in the Y-Fe-Al ternary system within the concentration region 50-100 at.% Al for an isothermal section at 1070 K by means of scanning electron microscopy and powder X-ray diffraction. Two ternary aluminides were observed,Y Fe Al (4#x#5.6) with the ThMn-type structure, a58.6467(9)-8.7604(7) A, c55.0374(6)-5.0504(5) A and YFe Al , x 122x 12 2 10˚Y bFe Al-type structure, a58.9649(6) A, b510.1568(6) A, c59.0113(6) A. The only binary which forms a prolonged solid solution 2 10r ange is YAl. The unit cell edge of the YFe Al compounds, MgCu-type structure, decreases with Fe content from 7.834(9) A for 2 x 22x 2 57ẍ 50 down to 7.689(4) A for x50.5. Fe Mossbauer spectroscopy data of YFe Al show an unusually large isomer shift for Fe in 2 10 Al-containing intermetallics and confirm that no magnetic ordering occurs down to 5 K.
Journal of Alloys and Compounds
Abstract In this work we report the results of our investigation of YbB66 as a potential high-tem... more Abstract In this work we report the results of our investigation of YbB66 as a potential high-temperature thermoelectric material. A high-quality single crystal has been grown by the optical floating zone method. Thermoelectric transport properties were measured in a temperature range of 373–973 K YbB66, like REB66 compounds in general, is a p-type semiconductor whose electrical properties can be described by Mott's variable range hopping mechanism. It shows very large Seebeck coefficient ranging from 588 μV K−1 at 373 K to 241 μV K−1 at 973 K and an electrical resistivity ρ that decreases by almost 4 orders of magnitude from 9.4×10−1 Ω m to 2.4 × 10−4 Ω m. Together with the low thermal conductivity of 2.6 W m−1 K−1 a maximum ZT close to 0.1 around 1000 K was determined with trend of sharp increase toward higher temperatures, which is similar to the previous report of SmB66, and significantly larger than previously reported for Y and Er phases of REB66. However, unlike SmB66, the effective magnetic moment suggests a trivalent state for Yb instead of mixed valence, which was determined by measuring the magnetic susceptibility from 2 to 300 K. The composition of YbB66 was indicated to be metal-rich, which actually may be the origin of the good performance.
ChemInform
Structure D 2000 Rietveld Refinement of the LnNi4B Compounds (Ln: Gd, Tb, Er).-The structure of t... more Structure D 2000 Rietveld Refinement of the LnNi4B Compounds (Ln: Gd, Tb, Er).-The structure of the title compounds annealed at 1070 K is determined by Rietveld refinement of powder XRD data. All the compounds crystallize with a CeCo4B-type structure in the hexagonal space group P6/mmm with Z = 2. The results disagree with crystal structure investigations of LnNi4B compounds reported previously, which could be an indication of strong dependence of structure formation on the temperature as well as on the nature of the rare earth metal.
Acta Materialia
The doping effect of zirconium on the structure, Seebeck coefficient and electrical resistivity o... more The doping effect of zirconium on the structure, Seebeck coefficient and electrical resistivity of β-rhombohedral B was studied for the metal rich concentration range Zr x B 100-x , 1.88≤x≤2.75. Structural studies proved the Zr atoms mainly in E and D voids for the metal rich compositions, and also elucidated the minor Zr occupancies of the N, F and A 1 holes. Seebeck coefficients were effectively shifted within a wide range of positive and negative values by varying the Zr content (p-type: S max ~ +420 µVK-1 at 673 K for x=1.88; n-type: S max ~-670 µVK-1 at 473 K for x=2.74). Electrical resistivities generally followed the Mott's relation for the variable-range hopping. Excellent compositional agreement has been observed between structural and thermoelectric properties discontinuities.
Inorganic Chemistry
Two borides, ScRu 2 B 3 and Sc 2 RuB 6 were obtained by argon-arc melting of the elements followe... more Two borides, ScRu 2 B 3 and Sc 2 RuB 6 were obtained by argon-arc melting of the elements followed by annealing at 800 ºC. ScRu 2 B 3 exhibits a new structure type with the space group Cmcm (a=3.0195(2) Å, b=15.4056(8) Å, c=5.4492(3) Å; single crystal X-ray data; R F 2 =0.0105). Sc 2 RuB 6 adopts the Y 2 ReB 6-type structure (space group Pbam; a=8.8545(2) Å, b=11.1620(3) Å, c=3.4760(1) Å; single crystal X-ray data; R F 2 =0.0185). ScRu 2 B 3 displays an unusual intergrowth of CeCo 3 B 2-and AlB 2-related slabs; a striking feature is a boat configuration of puckered boron hexagons within infinite B6 3 nets. Sc 2 RuB 6 presents twodimensional planar nets of condensed boron pentagons, hexagons and heptagons sandwiched between metal layers. In Sc/Y substituted Y 2 ReB 6-type, Y atoms are distributed exclusively inside the boron heptagons. Exploration of the Sc-RuB system at 800 ºC including binary boundaries employing EPMA and powder X-ray diffraction technique furthermore rules out the existence of previously reported "ScRuB 4 " but confirms the formation and crystal structure of Sc 2 Ru 5 B 4. ScRu 4 B 4 forms in cast alloys (LuRu 4 B 4-type structure; space group I4 1 /acd (no. 142), a=7.3543(2) Å, c=14.92137(8) Å). Cell parameters and atomic coordinates have been refined for ScRu 2 B 3 , Sc 2 RuB 6 and ScRu 4 B 4 in the scope of generalized gradient approximation. Ab initio electronic structure calculations indicate a moderate electronic density of states at the Fermi level situated near the upper edge of essentially filled d-bands. Electrical resistivity measurements characterize ScRu 2 B 3 and Sc 2 RuB 6 as metals in concord with electronic band structure calculations.
Journal of Alloys and Compounds
A new Pt-doped yttrium boride of the YB 50 family, YB 45-x Pt y , x=2.12, y=0.21 (space group Pba... more A new Pt-doped yttrium boride of the YB 50 family, YB 45-x Pt y , x=2.12, y=0.21 (space group Pbam, a=16.6246(4) Å, b=17.6453(4) Å, c=9.4167(2) Å), has been synthesized by arcmelting pure elements and subsequent annealing at 1123 K. A single crystal has been studied in order to assess the Pt-doping effect on the crystal structure. Insertion of Pt in two 4h interstitial sites of the boron atom framework leads to the transformation of-[B 12 ]-[B 12 ]icosahedral chain into-[B 11 ]-Pt-[B 11 ]-for 38.6% of them as well as, to a lesser extent, induces the disorder into the [B 15 ] polyhedron and neighboring interstitial B site (97.3% vs 2.7%).
Journal of Solid State Chemistry
Two boron rich phases were successfully synthesized by borothermal reduction of Yb oxide under va... more Two boron rich phases were successfully synthesized by borothermal reduction of Yb oxide under vacuum. For the new boron-poorer phase, the single phase was established at around [B]/[Yb]=43.3 at 1500 °C (Pbam space group; YB 50-type; a=16.5811(5) Å, b=17.5950(5) Å, c=9.4647(3) Å; powder X-ray diffraction; Rietveld refinement). The crystal structure of the boron-richer phase ([B]/[Yb]=56.0) has been elucidated by single crystal X-ray diffraction (3 Fm c space group; YB 66-type; a=23.3587(6) Å). Powder X-ray diffraction data of the alloy YbB~7 0 annealed at 1825 °C yielded, along with the YB 66-type compound (a=23.3691(2) Å), β-rh B as a secondary phase (m R3 space group, a=10.9298(3) Å, c=23.875(1) Å), for which the solubility of Yb was found to be below 1 at.%. Both YbB 43.3 and YbB 56.0 feature complicated boron atom frameworks which exhibit shorter B-B separations both within and between boron clusters as compared to those observed for prototype structures.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 6, 2017
A new member of the series of Th7 Fe3 -type derivative structures, h-(Pd0.86 Cu0.14 )7 B3 (≡Pd6.0... more A new member of the series of Th7 Fe3 -type derivative structures, h-(Pd0.86 Cu0.14 )7 B3 (≡Pd6.02 Cu0.98 B3 , unique structure type Pd6 CuB3 , space group P63 cm, a=12.9426(9) Å, c=4.8697(4) Å, single-crystal X-ray diffraction (XRD) data) was obtained from as cast alloys and alloys annealed at 600-650 °C. Further substitution of Cu by Pd led to formation of a Mn7 C3 -type structure, o-(Pd0.93 Cu0.07 )7 B3 (≡Pd6.51 Cu0.49 B3 , space group Pnma, a=4.8971(2) Å, b=7.5353(3) Å, c=12.9743(6) Å, single-crystal XRD). Isotypic LT h-(Pt0.70 Cu0.30 )7 B3 (≡Pt4.90 Cu2.10 B3 ) was observed in the Pt-Cu-B system as a low-temperature (LT) phase (T≤600 °C) (powder XRD), whereas the Th7 Fe3 -type (high-temperature (HT) h-(Pt0.73 Cu0.27 )7 B3 ≡Pt5.11 Cu1.89 B3 , space group P63 mc, a=7.4671(1) Å, c=4.9039(1) Å, powder XRD) proved to be stable at high temperature. The three structures are built of columns of face connected metal octahedra and columns of metal tetrahedra alternatingly fused by common ...
Russian Journal of Inorganic Chemistry, 1991
J Phys Condens Matter, 2002