Synthesis of New Thermoelectrics Using Modulated Elemental Reactants

1997 ◽  
Vol 478 ◽  
Author(s):  
Marc D. Hornbostel ◽  
Heike Sellinschegg ◽  
David C. Johnson
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Systematic Screening ◽  
X Ray ◽  
Low Temperature Annealing ◽  
Modulated Elemental Reactants ◽  
Ternary Metal ◽  
Elemental Reactants ◽  
Binary Compounds ◽  
New Compounds

AbstractA series of new, metastable ternary crystalline compounds with the skutterudite crystal structure have been synthesized using modulated elemental reactants. The initial reactants are made up of multiple repeats of a ˜25Å thick unit containing elemental layers of the desired ternary metal, iron and antimony. Low temperature annealing (150°C) results in interdiffusion of the elemental layers to form amorphous reaction intermediates. Annealing these intermediates at temperatures between 200°C and 250°C results in exothermic crystallization of the desired skutterudite crystal structure. Most of the new compounds prepared are only kinetically stable, decomposing exothermically to form thermodynamically more stable mixtures of binary compounds and elements. Low angle x-ray diffraction studies show that the resulting films are exceedingly smooth. These films have an ideal geometry for measuring properties of importance for thermoelectric devices—the Seebeck coefficient and the electrical conductivity. Thermal conductivity can be measured using a modification of the 3ω technique of Cahill. Samples can be produced rapidly, allowing for systematic screening and subsequent optimization as a function of composition and doping levels.

Synthesis of New Thermoelectric Materials Using Modulated Elementary Reactants

1998 ◽  
Vol 545 ◽  
Author(s):  
Heike Sellinschegg ◽  
Joshua R. Williams ◽  
Steven P. Maxwell ◽  
Douglas Sillars ◽  
David C. Johnson
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Reaction Intermediates ◽  
Ternary Compounds ◽  
Low Temperature Annealing ◽  
Modulated Elemental Reactants ◽  
Ternary Metal ◽  
Elemental Reactants ◽  
Binary Compounds

AbstractModulated elemental reactants have been used to synthesize metastable ternary compounds with the skutterudite crystal structure. The initial reactants are made up of multiple repeats of a unit containing elemental layers of a ternary metal, iron or cobalt (or a combination of these two) and antimony. The elemental layers interdiffuse upon low temperature annealing and form amorphous reaction intermediates. In this paper we target the compounds PbxFe4−yCoySb12. On annealing at temperatures between 12° and 150° C (depending on the composition) crystallization of the skutterudite structure occurs. The compounds are only kinetically stable, decomposing into a mixture of binary compounds upon annealing past a temperature of about 600°C. Preliminary data for the Seebeck coefficient and the electrical conductivity was collected The thermoelectric properties of the lead cobalt antimony skutterudite - films were measured as a function of lead occupancy.

RE2B8O15 (RE = La, Pr, Nd) – syntheses of three new rare earth borates isotypic to Ce2B8O15

2016 ◽  
Vol 71 (5) ◽  
pp. 535-542 ◽  
Author(s):  
Matthias Glätzle ◽  
Gregor J. Hoerder ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Single Crystal ◽  
Infrared Spectra ◽  
Diffraction Data ◽  
Boron Oxide ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds

AbstractThe rare earth borates RE2B8O15 (RE = La, Pr, Nd) were synthesized in a Walker-type multianvil apparatus under conditions of 5.5 GPa and 1100 °C. Starting from the corresponding rare earth oxides and boron oxide, the syntheses yielded crystalline products of all new compounds that allowed crystal structure analyses based on single-crystal X-ray diffraction data for La2B8O15 and Nd2B8O15. The compound Pr2B8O15 could be characterized via X-ray powder diffractometry. The results show that the new compounds crystallize isotypically to Ce2B8O15 in the monoclinic space group P2/c. The infrared spectra of RE2B8O15 (RE = La, Pr, Nd) have also been studied.

scholarly journals Monofluorophosphates—New Examples and a Survey of the PO3F2− Anion

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 45-73
Author(s):  
Matthias Weil
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Inorganic Compounds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type D ◽  
Index 2 ◽  
New Compounds ◽  
Relationship Of ◽  
Tetrahedral Anion

During a systematic study of monofluorophosphates, i.e., compounds comprising the tetrahedral anion PO3F2−, twelve, for the most part new, compounds were obtained from aqueous solutions. Crystal structure refinements based on single crystal X-ray diffraction data revealed the previously unknown crystal structures of CdPO3F(H2O)2, Cr2(PO3F)3(H2O)18.8, Pb2(PO3F)Cl2(H2O), (NH4)2M(PO3F)2(H2O)2 (M = Mg, Mn, Co), NH4Cr(PO3F)2(H2O)6, NH4Cu2(H3O2)(PO3F)2, (NH4)2Zn(PO3F)2(H2O)0.2, and (NH4)2Zn3(PO3F)4(H2O), as well as redeterminations of ZnPO3F(H2O)2.5 and (NH4)2Ni(PO3F)2(H2O)6. From the previously unknown crystal structures, CdPO3F(H2O)2 (space group P-1), Cr2(PO3F)3(H2O)18.8 (P-1), Pb2(PO3F)Cl2(H2O) (Pnma), NH4Cr(PO3F)2(H2O)6 (R-3m), (NH4)2Zn(PO3F)2(H2O)0.2 (C2/c), and (NH4)2Zn3(PO3F)4(H2O) (I-43d) each crystallizes in an unique crystal structure, whereas compounds (NH4)2M(PO3F)2(H2O)2 (M = Mg, Co) crystallize in the (NH4)2Cu(PO3F)2(H2O)2 type of structure (C2/m) and (NH4)2Mn(PO3F)2(H2O)2 in a subgroup thereof (P21/n, with a klassengleiche relationship of index 2), and NH4Cu2(H3O2)(PO3F)2 (C2/m) crystallizes isotypically with natrochalcite-type KCu2(H3O2)(SO4)2. A survey on the PO3F2− anion, including database entries of all inorganic compounds comprising this group, revealed mean bond lengths of P–O = 1.506(13) Å, P–F = 1.578(20) Å, and angles of O–P–O = 113.7(1.7)° and O–P–F = 104.8(1.7)°, using a dataset of 88 independent PO3F2− anions or entities. For those crystal structures of monofluorophosphates where hydrogen bonding is present, in the vast majority of cases, hydrogen bonds of the type D–H···F–P (D = O, N) are not developed.

Synthesis of (Bi2Te3)x(TiTe2)y and (Bi2Te3)x(TiTe2)3 Superlattices

2005 ◽  
Vol 886 ◽  
Author(s):  
Mary Smeller ◽  
Fred R. Harris ◽  
David C. Johnson
Keyword(s):  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Characteristic Structure ◽  
X Ray ◽  
Modulated Elemental Reactants ◽  
Annealing Conditions ◽  
Linear Behavior ◽  
Deposition Parameters ◽  
Elemental Reactants ◽  
Diffraction Patterns

ABSTRACTThe synthesis of (Bi2Te3)x(TiTe2)x and (Bi2Te3)x(TiTe2)3 superlattices using modulated elemental reactants was successfully accomplished. This required the calibration of the deposition parameters to achieve both the desired atomic compositions of the constituent layers and the deposition of the absolute amounts of each of the components to yield the title compounds. Proper annealing conditions were determined from an investigation of the x-ray diffraction patterns of a superlattice sample as a function of annealing temperature. The change in lattice parameters as a function of x showed the expected linear behavior with slopes consistent with values expected from the published lattice parameters of the binary components. Rietveld refinement showed that the characteristic structure of the binary components is maintained in the superlattices studied.

Darstellung und Struktur von NaAu3Si und NaAu3Ge / Preparation and Crystal Structure of NaAu3Si and NaAu3Ge

1980 ◽  
Vol 35 (11) ◽  
pp. 1482-1483 ◽  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Ternary Systems ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
New Compounds

Abstract In the course of our investigations of the ternary systems Na-Au-Si(Ge) we obtained the new compounds NaAu3Si and NaAu3Ge. Their crystal structure has been determined from single crystal X-ray diffraction data. They crystallize in the cubic space group Pa 3 with unit cell parameters a = 891,6 pm and a = 902,1 pm, resp., and Z = 8.

Preparation of [(Bi2Te3)x(HfTe2)]y Superlattices

2005 ◽  
Vol 886 ◽  
Author(s):  
Benjamin Allen Schmid ◽  
Fred R Harris ◽  
David C Johnson
Keyword(s):  
Annealing Temperature ◽  
Amorphous State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modulated Elemental Reactants ◽  
Elemental Reactants

ABSTRACTThe synthesis of a number of (Bi2Te3)x(HfTe2)y superlattices was accomplished using the modulated elemental reactants (MER) method. The samples were characterized using X-ray reflectivity and X-ray diffraction in the as deposited (amorphous) state and as a function of annealing temperature and time.

Synthese, Kristallstruktur und Spektroskopische Charakterisierung des Phosphaniminato-Komplexes [Cl2AlNPCl3]2 und des Phosphanimin-Komplexes [Me3SiNPCl3 · AlCl3]/Synthesis, Crystal Structure, and Spectroscopic Characterization of the Phosphorane Iminato Complex [Cl2AlNPCl3]2, and of the Phosphane Imine Complex [Me3SiNPCl3 · AlCl3]

2002 ◽  
Vol 57 (11) ◽  
pp. 1237-1243 ◽  
Author(s):  
Britta Jächke ◽  
Martin Jansen
Keyword(s):  
Crystal Structure ◽  
Point Group ◽  
Spectroscopic Characterization ◽  
Membered Ring ◽  
Site Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor Acceptor ◽  
New Compounds

Reaction of Me3SiNPCl3 with AlCl3 yields the donor-acceptor complex [Me3SiNPCl3 · AlCl3] (1). Thermal treatment of 1 and simultaneously removing the by-product Me3SiCl results in the formation of [Cl2AlNPCl3]2 (2). Crystallization of 2 from CH2Cl2 yields colorless crystals which have been characterized by single crystal X-ray diffraction analysis (P1̄, a = 719.1(2), b = 843.5(2), c = 857.4(2) pm, α = 64.23(1), β = 76.62(1), γ = 68.21(1)°, Z = 1, R1 = 0.0498). The molecule exhibits site symmetry Ci (point group approximately C2h) and shows as a characteristic feature a planar, almost square Al2N2 four-membered ring with Al-N distances of 187.5(3) and 187.9(3) pm. The phosphorus atoms of the PCl3-groups attached to the nitrogen atoms are almost located in the same plane as defined by the Al2N2-ring. Both new compounds have been characterized by IR, NMR, and MS spectroscopy.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

Crystal Forms of Semisynthetic Ergot Alkaloid Terguride

2002 ◽  
Vol 67 (4) ◽  
pp. 479-489 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
Ladislav Cvak ◽  
Alexandr Jegorov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ergot Alkaloid ◽  
Simplified Model ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
X Ray Diffraction ◽  
Torsion Angles ◽  
Crystal Forms ◽  
X Ray ◽  
Independent Molecules

Two new structures of semisynthetic ergot alkaloid terguride created by unusual number of symmetry-independent molecules were determined by X-ray diffraction methods at 150 K. Form A (monoclinic, P212121, Z = 12) contains three symmetry-independent terguride molecules and two molecules of water in the asymmetric part of the unit cell. The form CA (monoclinic, P21, Z = 8) is an anhydrate remarkable by the presence of four symmetry-independent molecules in the crystal structure. Conformations of twelve symmetry-independent molecules that were found in four already described terguride structures are compared with torsion angles obtained by ab initio quantum-mechanical calculations for the simplified model of N-cyclohexyl-N'-diethylurea.

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