scholarly journals Scandium-rich ternary coloring variants of the cubic Ag7+xMg26–x type

2020 ◽  
Vol 151 (11) ◽  
pp. 1673-1679
Author(s):  
Nataliya L. Gulay ◽  
Yaroslav M. Kalychak ◽  
Maximilian K. Reimann ◽  
Christian Paulsen ◽  
Jutta Kösters ◽  
...  
Keyword(s):  
Single Crystal ◽  
Intermetallic Compounds ◽  
Induction Furnace ◽  
Site Occupancy ◽  
Complex Structures ◽  
Occupied Site ◽  
X Ray

Abstract The scandium-rich intermetallic compounds Sc50T13In3 (T = Ni, Ru, Pd) were synthesized from the elements in sealed tantalum crucibles in an induction furnace. The samples were studied through Guinier powder patterns and their structures were refined from single-crystal X-ray diffractometer data. The Sc50T13In3 phases are site occupancy (coloring) variants of the aristotype Ag7+xMg26–x (Fm$$ \bar{3} $$ 3 ¯ , cF264). Refinements of the occupancy parameters indicated one mixed occupied site for each crystal, leading to the refined compositions Sc50Ni13.16(1)In2.84(1), Sc49.59(1)Ru13In3.41(1), and Sc50Pd13.65(2)In2.35(2). The complex structures can be explained by a condensation of cubes (CN 8), sphenocorona (CN 10), and icosahedra (CN 12). The samples with nickel and palladium are Pauli paramagnets. Graphic abstract

Copper-rich Intermetallic Compounds RECu9Cd2(RE = La, Ce, Pr, Nd) with YNi9In2-type Structure

2012 ◽  
Vol 67 (11) ◽  
pp. 1225-1228 ◽  
Author(s):  
Michael Johnscher ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Intermetallic Compounds ◽  
Induction Furnace ◽  
Three Dimensional ◽  
Pair Formation ◽  
Type Structure ◽  
X Ray Diffraction ◽  
X Ray

The YNi9In2-type copper-rich compounds RECu9Cd2 (RE=La, Ce, Pr, Nd) were synthesized directly from the elements in sealed niobium ampoules in an induction furnace and were characterized by powder X-ray diffraction. The structure of PrCu9Cd2 was refined from single-crystal Xray diffractometer data: P4/mbm, a=849.0(3), c=498.2(3) pm, wR2=0.0418, 374 F2 values, 23 variables. The structure has two striking polyhedral motifs: Pr@Cu16Cd4 and Cu2@Cu8Cd4. The packing of these polyhedra describes the whole structure. The copper and cadmium atoms build up a three-dimensional [Cu9Cd2] network with broader ranges of Cu-Cu (246 - 274 pm) and Cu-Cd (272 - 288 pm) distances. The cadmium atoms show segregation through pair formation with Cd-Cd distances of 288 pm.

Ternary Antimonides RE4T7Sb6 (RE=Gd–Lu; T =Ru, Rh) with Cubic U4Re7Si6-type Structure

2013 ◽  
Vol 68 (9) ◽  
pp. 971-978 ◽  
Author(s):  
Inga Schellenberg ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Magnetic Moment ◽  
Induction Furnace ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Arc Melting ◽  
Intermediate Valent

The ternary antimonides RE4T7Sb6 (RE=Gd-Lu; T =Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Im3m with a=862.9(2) pm, wR2=0.0296, 163 F2 values for Er4Ru7Sb6; a=864.1(1) pm, wR2=0.1423, 153 F2 values for Yb4Ru7Sb6; a=872.0(2) pm, wR2=0.0427, 172 F2 values for Tb4Rh7Sb6; and a=868.0(2) pm, wR2=0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE=Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion

H-bonding scheme in allactite: a combined single-crystal X-ray and neutron diffraction, optical absorption spectroscopy, FTIR and EPMA-WDS study

2016 ◽  
Vol 80 (5) ◽  
pp. 719-732 ◽  
Author(s):  
G. Diego Gatta ◽  
Ferdinando Bosi ◽  
Maria Teresa Fernandez Diaz ◽  
Ulf Hålenius
Keyword(s):  
Neutron Diffraction ◽  
Optical Absorption ◽  
Single Crystal ◽  
Absorption Spectroscopy ◽  
Structure Refinement ◽  
Site Occupancy ◽  
Optical Absorption Spectroscopy ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Bonding Scheme

AbsatractThe crystal chemistry of allactite from Långban, Värmland (Sweden) was investigated by single-crystal X-ray and neutron diffraction, optical absorption spectroscopy, Fourier-transform infra-red spectroscopy (FTIR) and electron microprobe analysis by wavelength-dispersive spectroscopy (EPMA-WDS). The optical spectra indicate the presence of Mn in valence state 2+ only. Assuming 16 O atoms per formula unit, arsenic as As5+and the (OH) content calculated by charge balance, the resulting formula based on the EPMA-WDS data is (Mn2+6.73Ca0.13Mg0.12Zn0.02)∑7.00(As5+)2.00O16H8, very close to the ideal composition Mn7(AsO4)2(OH)8. In the unpolarized FTIR spectrum of allactite, fundamental (OH)-stretching bands are observed at 3236, 3288, 3387, 3446, 3484, 3562 and 3570 cm–1, suggesting that a number of OH environments, with different hydrogen bond strengths, occur in the structure. The neutron structure refinement shows that four independent H sites occur in allactite with full site occupancy, all as members of hydroxyl groups. The complex hydrogen-bonding scheme in the allactite structure is now well defined, with at least nine hydrogen bonds energetically favourable with mono-, bi- and trifurcated configurations.

New Intermetallic Compounds RE4Co2Mg3 (RE = Pr, Gd, Tb, Dy) – Syntheses, Structure, and Chemical Bonding

2007 ◽  
Vol 62 (2) ◽  
pp. 162-168 ◽  
Author(s):  
Selcan Tuncel ◽  
Ute Ch. Rodewald ◽  
Samir F. Matar ◽  
Bernard Chevalier ◽  
Rainer Pöttgena
Keyword(s):  
Single Crystal ◽  
Intermetallic Compounds ◽  
Chemical Bonding ◽  
Structural Features ◽  
Induction Melting ◽  
Geometrical Constraint ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bonding Analysis ◽  
Magnesium Compounds

The magnesium compounds RE4Co2Mg3 (RE = Pr, Gd, Tb, Dy) were prepared by induction melting of the elements in sealed tantalum tubes. The samples were studied by powder X-ray diffraction. The structures of the gadolinium and of the terbium compound were refined from single crystal diffractometer data: Nd4Co2Mg3-type, P2/m, Z = 1, a = 754.0(4), b = 374.1(1), c = 822.5(3) pm, β = 109.65(4)°, wR2 = 0.0649, 730 F2 values for Gd4Co2Mg3 and a = 750.4(2), b = 372.86(6), c = 819.5(2) pm, β = 109.48(3)°, wR2 = 0.0398, 888 F2 values for Tb4Co2Mg3 with 30 variables each. The RE4Co2Mg3 structures are 3 : 1 intergrowth variants of distorted CsCl and AlB2 related slabs of compositions REMg and RECo2. Characteristic structural features (exemplary for Tb4Co2Mg3) are relatively short Tb-Co (271 pm), Co-Co (232 pm) and Mg-Mg (314 pm) distances. The latter are a geometrical constraint of the distortion of the REMg and RECo2 slabs. Chemical bonding analysis (ELF and ECOV data) for Gd4Co2Mg3 reveals strong Gd-Co bonding followed by Mg-Co, while the Mg-Mg interactions can be considered as weak. The Co-Co contacts are only weakly bonding. The bonding and antibonding states are almost filled.

scholarly journals Dendritic Structure Analysis of CMSX-4 Cored Turbine Blades Roots

2016 ◽  
Vol 61 (2) ◽  
pp. 1129-1134 ◽  
Author(s):  
J. Krawczyk
Keyword(s):  
Single Crystal ◽  
Cross Sections ◽  
Induction Furnace ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
Root Structure ◽  
Sem Images ◽  
X Ray ◽  
Nickel Based Superalloy

Abstract The microstructure of as-cast cored turbine blades roots, made of the single-crystal CMSX-4 nickel-based superalloy was investigated. Analysed blades were obtained by directional solidification technique in the industrial ALD Bridgman induction furnace. The investigations of the microstructure of blades roots were performed using SEM and X-ray techniques including diffraction topography with the use of Auleytner method. Characteristic shapes of dendrites with various arrangement were observed on the SEM images taken from the cross-sections, made transversely to the main blades axis. The differences in quality of the structure in particular areas of blades roots were revealed. Based on the results, the influence of cooling bores on blades root structure was analysed and the changes in the distribution and geometry of cooling bores were proposed.

Rare Earth-rich Cadmium Compounds RE4TCd (T = Ni, Pd, Ir, Pt)

2008 ◽  
Vol 63 (9) ◽  
pp. 1127-1130 ◽  
Author(s):  
Falko M. Schappacher ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Single Crystal ◽  
Intermetallic Compounds ◽  
Three Dimensional ◽  
Type Structure ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Cadmium Compounds

New intermetallic compounds RE4TCd (RE = Y, La-Nd, Sm, Gd-Tm, Lu; T = Ni, Pd, Ir, Pt) were synthesized by melting of the elements in sealed tantalum tubes in a highfrequency furnace. They crystallize with the Gd4RhIn-type structure, space group F 4̄3m, Z = 16. The four gadolinium compounds were characterized by single crystal X-ray diffractometer data: a = 1361.7(1) pm, wR2 = 0.062, 456 F2 values, 19 variables for Gd4NiCd; a = 1382.1(2) pm, wR2 = 0.077, 451 F2 values, 19 variables for Gd4PdCd; a = 1363.6(2) pm, wR2 = 0.045, 494 F2 values, 19 variables for Gd4IrCd; a = 1379.0(1) pm, wR2 = 0.045, 448 F2 values, 19 variables for Gd4PtCd. The rare earth atoms build up transition metal-centered trigonal prisms which are condensed via common corners and edges, leading to three-dimensional adamantane-related networks. The cadmium atoms form Cd4 tetrahedra which fill voids left in the prisms’ network.

Structure and Magnetic Properties of GdPt2In and GdPt2Sn

2009 ◽  
Vol 64 (2) ◽  
pp. 170-174 ◽  
Author(s):  
Birgit Heying ◽  
Ute Ch. Rodewald ◽  
Wilfried Hermes ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Intermetallic Compounds ◽  
Coordination Number ◽  
Magnetic Moment ◽  
Space Group ◽  
X Ray ◽  
Arc Melting ◽  
Experimental Magnetic Moment

The platinum-rich intermetallic compounds GdPt2In and GdPt2Sn were synthesized by arc-melting of the elements and subsequent annealing. The structures were refined from single crystal X-ray diffractometer data: ZrPt2Al type, space group P63/mmc, a = 455.1(1), c = 899.3(3) pm, wR2 = 0.0361, 166 F2 values, 9 variables for GdPt2In, and a = 453.2(1), c = 906.5(2) pm, wR2 = 0.0915, 166 F2 values, 9 variables for GdPt2Sn. The platinum and indium (tin) atoms build up threedimensional [Pt2In] and [Pt2Sn] networks with short Pt-In (Pt-Sn) distances and Pt2 dumb-bells (290 and 297 pm in GdPt2In and GdPt2Sn). The gadolinium atoms have coordination number 14 with 8 Pt and 6 In (Sn) neighbors. Magnetic susceptibility measurements on GdPt2In show Curie-Weiss behavior with an experimental magnetic moment of 8.06(2) μB/Gd atom. GdPt2In orders ferromagnetically at 27.7(2) K

A single-crystal neutron and X-ray diffraction study of a Li, Be-bearing brittle mica

2014 ◽  
Vol 78 (1) ◽  
pp. 55-72 ◽  
Author(s):  
G. D. Gatta ◽  
G. Nénert ◽  
G. Guastella ◽  
P. Lotti ◽  
A. Guastoni ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Single Crystal ◽  
Scattering Length ◽  
Structure Refinement ◽  
Site Occupancy ◽  
Emission Spectrometry ◽  
X Ray Diffraction ◽  
Plasma Atomic Emission Spectrometry ◽  
X Ray ◽  
Final Population

AbstractThe crystal chemistry of a meso-octahedral Li,Be-bearing mica from the Harding pegmatite (Dixon, Taos County, New Mexico, USA) has been investigated by constant-wavelength single-crystal neutron diffraction at 20 K, single-crystal X-ray diffraction at 100 K and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The chemical composition based on ICP-AES analysis leads to the following chemical formula (calculated on the basis of 12 oxygen atoms):Ca(Na0.26K0.04Ca0.69)∑0.99M(Li0.29Mg0.03Fe0.023+Al1.78)∑2.12T(Al1.73Be0.16Si2.11)S4.00O12H2.53. The apparent excess of H is probably due to the fact that the fraction of H2O was assumed by difference to 100 wt.%, and slightly overestimated. On the basis of the previous experimental findings on Li,Be-bearing mica, X-ray (at 100 K) and neutron (at 20 K) structure refinements were performed in the space groupsCcandC2/c. The neutron structure refinement in the space groupCcoffers a view about the (Al,Be,Si)-tetrahedral ordering: the best fit of the refinement was reached with theT1 andT4 sites occupied by (Be + Al) andT2 andT3 fully occupied by Si. This leads to a final population ofT(Al1.88Be0.12Si2.00)∑4.00p.f.u., in reasonable agreement with the chemical analysis. The neutron refinement provides unambigous evidence of the occurrence of Li at theM1 site. The refined fraction of Li at theM1 site ranges between 0.27 and 0.29 a.p.f.u., in excellent agreement with the chemical analysis. The presence of Li, at least at a significant level, at theM2 (andM3) site can be ruled out, as a full site occupancy with the scattering length of Al was obtained. The location of the H sites and the complex hydrogen-bonding scheme are described. A comparison between the structure features of this Li,Be-mica and other brittle micas is carried out.

Sr2Au6Al3 and Eu2Au6Al3 – First Representatives of the Sr2Au6Zn3 Type with Aluminum Triangles

2014 ◽  
Vol 69 (1) ◽  
pp. 121-124 ◽  
Author(s):  
Birgit Gerke ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Induction Furnace ◽  
Small Degree ◽  
Stacking Sequence ◽  
X Ray Diffraction ◽  
X Ray

The aluminides Sr2Au6Al3 and Eu2Au6Al3 were synthesized by melting the elements in sealed tantalum tubes in a muffle or induction furnace. The samples were characterized by powder and single-crystal X-ray diffraction: Sr2Au6Zn3 type, R3̄c, a = 845.1(1), c = 2177.2(3) pm, wR2=0.0263, 520 F2 values, 20 variables for Sr2Au6.18(1)Al2.82(1), and a = 838.0(1), c = 2177.1(7) pm, wR2 = 0.0276, 510 F2 values, 19 variables for Eu2Au6Al3. The gold atoms build up diamond-related networks of slightly distorted tetrahedra in the stacking sequence of the 6R polytype (289 - 296 pm Au-Au in Eu2Au6Al3). The voids left by this network are filled in an ordered manner by strontium (europium) atoms and the rare motif of Al3 triangles (286 pm Al-Al in Eu2Au6Al3). The Al3 triangles in Sr2Au6.18(1)Al2.82(1) show a small degree of Al/Au mixing.

Interdiffusion Behavior of Electroplated Platinum-Iridium Alloys on Nickel-Base Single Crystal Superalloy TMS-82+

2006 ◽  
Vol 522-523 ◽  
pp. 293-300
Author(s):  
Ying Na Wu ◽  
Aya S. Suzuki ◽  
Hideyuki Murakami ◽  
Seiji Kuroda
Keyword(s):  
Chemical Composition ◽  
Single Crystal ◽  
Intermetallic Compounds ◽  
Single Crystal Superalloy ◽  
Outward Diffusion ◽  
X Ray ◽  
Diffusion Treatment ◽  
Ordered Intermetallic ◽  
Nickel Base ◽  
Depth Concentration

In the present study, platinum-iridium alloys (Ir = 15.8, 27.3, 36.1, 100at.%) were electroplated on a nickel-base single crystal superalloy TMS-82+ followed by a diffusion treatment at 1373K for 1 h. Interdiffusion behavior between the Pt-Ir films and substrates was investigated in terms of chemical composition, phase constitution and morphology. X-ray analysis revealed that annealed specimens consisted of several fcc solid solutioned phases with various lattice parameters, together with ordered intermetallic compounds (L12-(Pt,Ni)3Al and B2-(Ir,Ni)Al), due to the inward diffusion of Pt and Ir from the electrodeposited films to the superalloy substrates, and the outward diffusion of solute elements (Ni, Al, Cr, Co) in the superalloy substrates into the films during annealing. The depth concentration analysis indicated that the Pt-36.1Ir film effectively retarded the outward diffusion of solute elements, especially nickel, from the substrate.

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