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Abstract
Abstract
The new samarium germanide SmGe3 is obtained by high-pressure high-temperature synthesis of pre-reacted mixtures of samarium and germanium at a pressure of 9.5 GPa and temperatures between 1073 and 1273 K. SmGe3 decomposes at 470(5) K into SmGe2, α-Sm3Ge5 and a hitherto unknown phase. SmGe3 exhibits a superstructure of the cubic Cu3Au-type. Transmission electron microscopy measurements of crystalline particles and prepared lamellae indicate a high density of defects on the nanoscale. Selected area electron diffraction and elaborate X-ray powder diffraction measurements consistently indicate a 2a
0 × 2a
0 × 2a
0 superstructure adopting space group
F
m
3
¯
m
$Fm\overline{3}m$
with a = 8.6719(2) Å.
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2
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Schwarz U, Castillo R, Hübner JM, Wosylus A, Prots Y, Bobnar M, Grin Y. The untypical high-pressure Zintl phase SrGe6. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2020. [DOI: 10.1515/znb-2019-0197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
The binary strontium germanide SrGe6 was synthesized at high-pressure high-temperature conditions of approximately 10 GPa and typically 1400 K before quenching to ambient conditions. At ambient pressure, SrGe6 decomposes in a monotropic fashion at T = 680(10) K into SrGe2 and Ge, indicating its metastable character. Single-crystal X-ray diffraction data indicate that the compound SrGe6 adopts a new monoclinic structure type comprising a unique three-dimensional framework of germanium atoms with unusual cages hosting the strontium cations. Quantum chemical analysis of the chemical bonding shows that the framework consists of three- and four- bonded germanium atoms yielding the precise electron count Sr[(4bGe0]4[(3b)Ge−]2 in accordance with the 8 − N rule and the Zintl concept. Conflicting with that, a pseudo-gap in the electronic density of states appears clearly below the Fermi level, and elaborate bonding analysis reveals additional Sr–Ge interactions in the concave coordination polyhedron of the strontium atoms.
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Affiliation(s)
- Ulrich Schwarz
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Rodrigo Castillo
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Julia M. Hübner
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Aron Wosylus
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Yurii Prots
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Matej Bobnar
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Yuri Grin
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
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3
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Hübner JM, Akselrud L, Schnelle W, Burkhardt U, Bobnar M, Prots Y, Grin Y, Schwarz U. High-Pressure Synthesis and Chemical Bonding of Barium Trisilicide BaSi₃. MATERIALS 2019; 12:ma12010145. [PMID: 30621176 PMCID: PMC6337167 DOI: 10.3390/ma12010145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/22/2018] [Accepted: 12/26/2018] [Indexed: 11/16/2022]
Abstract
BaSi3 is obtained at pressures between 12(2) and 15(2) GPa and temperatures from 800(80) and 1050(105) K applied for one to five hours before quenching. The new trisilicide crystallizes in the space group I4¯2m (no. 121) and adopts a unique atomic arrangement which is a distorted variant of the CaGe3 type. At ambient pressure and 570(5) K, the compound decomposes in an exothermal reaction into (hP3)BaSi2 and two amorphous silicon-rich phases. Chemical bonding analysis reveals covalent bonding in the silicon partial structure and polar multicenter interactions between the silicon layers and the barium atoms. The temperature dependence of electrical resistivity and magnetic susceptibility measurements indicate metallic behavior.
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Affiliation(s)
- Julia-Maria Hübner
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Lev Akselrud
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Walter Schnelle
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Ulrich Burkhardt
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Matej Bobnar
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Yurii Prots
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Yuri Grin
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
| | - Ulrich Schwarz
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany.
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Schwarz U, Castillo R, Wosylus A, Akselrud L, Prots Y, Wahl B, Doert T, Bobnar M, Grin Y. Modulated vacancy ordering in SrGe6−
x
(x≈0.45). ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2018. [DOI: 10.1515/znb-2018-0200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The structural properties of modulated SrGe6−
x
(x≈0.45) were investigated by means of single-crystal and powder X-ray diffraction combined with quantum chemical calculations. The framework compound SrGe6−
x
adopts a defect variant of the EuGa2Ge4-type crystal structure. Samples of the binary compound with nominal compositions 0≤x≤0.5 were synthesized at pressures from 5 to 6 GPa and a temperature of typically 1400 K. The product reveals diffraction peaks of the EuGa2Ge4-type subcell plus additional reflections indicating an ordered superstructure. Detailed crystal structure analysis evidences the incommensurate nature of the superstructure and a modulation of the vacancy ordering in the germanium network. The computations have shown that the non-stoichiometric composition of the framework with its local defect organization affects the calculated charge of the strontium anions. Although the chemical composition is close to a charge-balanced situation, temperature-dependent resistivity measurements showed metal-type conductivity. At ambient pressure SrGe6−
x
decomposes exothermally and irreversibly at T=680(10) K into SrGe2 and germanium, indicating its metastable nature at ambient pressure.
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Affiliation(s)
- Ulrich Schwarz
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Rodrigo Castillo
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Aron Wosylus
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Lev Akselrud
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
- Department of Inorganic Chemistry , Ivan Franko National University of Lviv , Kyryla i Mefodiya St. 6 , Lviv, 79005 , Ukraine
| | - Yurii Prots
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Bernhard Wahl
- Technische Universität Dresden, Institut für Anorganische Chemie II , Bergstraße 66 , 01069 Dresden , Germany
| | - Thomas Doert
- Technische Universität Dresden, Institut für Anorganische Chemie II , Bergstraße 66 , 01069 Dresden , Germany
| | - Matej Bobnar
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Yuri Grin
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
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Hübner JM, Bobnar M, Akselrud L, Prots Y, Grin Y, Schwarz U. Lutetium Trigermanide LuGe 3: High-Pressure Synthesis, Superconductivity, and Chemical Bonding. Inorg Chem 2018; 57:10295-10302. [PMID: 30070106 DOI: 10.1021/acs.inorgchem.8b01510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
LuGe3 was obtained under high-pressure and high-temperature conditions at pressures between 8(1) and 14(2) GPa and at temperatures in the range from 1100(150) to 1500(150) K. The high-pressure phase is isotypic to DyGe3 and decomposes at ambient pressure and T = 690 K mainly into ( cF8)Ge and LuGe2- x. Chemical bonding analysis of LuGe3 reveals two-center electron-deficient Ge-Ge bonds, multicenter polar Lu-Ge interactions, and lone pairs on germanium. Magnetic susceptibility, specific heat, and electrical conductivity measurements indicate transition into a superconducting state below Tc = 3.3(3) K.
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Affiliation(s)
- Julia-Maria Hübner
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Matej Bobnar
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Lev Akselrud
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Yurii Prots
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Yuri Grin
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
| | - Ulrich Schwarz
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40 , 01187 Dresden , Germany
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Solokha P, Minetti R, De Negri S, Pereira LCJ, Gonçalves AP, Saccone A. The
R
MgSn
2
Series of Compounds (
R
= Rare Earth Metal): Synthesis, Crystal Structure, and Magnetic Measurements. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Pavlo Solokha
- Dipartimento di Chimica e Chimica Industriale Università di Genova via Dodecaneso 31 16146 Genova Italy
| | - Riccardo Minetti
- Dipartimento di Chimica e Chimica Industriale Università di Genova via Dodecaneso 31 16146 Genova Italy
| | - Serena De Negri
- Dipartimento di Chimica e Chimica Industriale Università di Genova via Dodecaneso 31 16146 Genova Italy
| | - Laura Cristina J. Pereira
- Centro de Ciências e Tecnologias Nucleares Instituto Superior Técnico, EN 10 Universidade de Lisboa ao Km 139.7 2695‐066 Bobadela LRS Portugal
| | - Antonio P. Gonçalves
- Centro de Ciências e Tecnologias Nucleares Instituto Superior Técnico, EN 10 Universidade de Lisboa ao Km 139.7 2695‐066 Bobadela LRS Portugal
| | - Adriana Saccone
- Dipartimento di Chimica e Chimica Industriale Università di Genova via Dodecaneso 31 16146 Genova Italy
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