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Grochala W. A focus on penetration index - a new descriptor of chemical bonding. Chem Sci 2023; 14:11597-11600. [PMID: 37920354 PMCID: PMC10619538 DOI: 10.1039/d3sc90191b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023] Open
Abstract
Electron clouds surrounding atoms interpenetrate in a molecule, due to weak van der Waals interactions or formation of a genuine chemical bond. Now, Alvarez and Echeverría (S. Alvarez, J. Echeverría, Chem. Sci., 2023, https://doi.org/10.1039/D3SC02238B) suggest a simple descriptor of how deep this interpenetration is, calling it a penetration index, i [Å]. This property may easily be related to a combined thickness of the van der Waals regions of two bond-forming atoms, thus giving rise to a dimensionless penetration index, pAB [%]. How far this new index may take us will be discussed in this article.
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Affiliation(s)
- Wojciech Grochala
- Center of New Technologies, University of Warsaw Zwirki i Wigury 93 02-089 Warsaw Poland
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Jezierski D, Koteras K, Domański M, Połczyński P, Mazej Z, Lorenzana J, Grochala W. Unexpected Coexisting Solid Solutions in the Quasi-Binary Ag (II) F 2 /Cu (II) F 2 Phase Diagram. Chemistry 2023; 29:e202301092. [PMID: 37254788 DOI: 10.1002/chem.202301092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 06/01/2023]
Abstract
High-temperature solid-state reaction between orthorhombic AgF2 and monoclinic CuF2 (y=0.15, 0.3, 0.4, 0.5) in a fluorine atmosphere resulted in coexisting solid solutions of Cu-poor orthorhombic and Cu-rich monoclinic phases with stoichiometry Ag1-x Cux F2 . Based on X-ray powder diffraction analyses, the mutual solubility in the orthorhombic phase (AgF2 : Cu) appears to be at an upper limit of Cu concentration of 30 mol % (Ag0.7 Cu0.3 F2 ), while the monoclinic phase (CuF2 : Ag) can form a nearly stoichiometric Cu : Ag=1 : 1 solid solution (Cu0.56 Ag0.44 F2 ), preserving the CuF2 crystal structure. Experimental data and DFT calculations showed that AgF2 : Cu and CuF2 : Ag solid solutions deviate from the classical Vegard's law. Magnetic measurements of Ag1-x Cux F2 showed that the Néel temperature (TN ) decreases with increasing Cu content in both phases. Likewise, theoretical DFT+U calculations for Ag1-x Cux F2 showed that the progressive substitution of Ag by Cu decreases the magnetic interaction strength |J2D | in both structures. Electrical conductivity measurements of Ag0.85 Cu0.15 F2 showed a modest increase in specific ionic conductivity (3.71 ⋅ 10-13 ±2.6 ⋅ 10-15 S/cm) as compared to pure AgF2 (1.85 ⋅ 10-13± 1.2 ⋅ 10-15 S/cm), indicating the formation of a vacancy- or F adatom-free metal difluoride sample.
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Affiliation(s)
- D Jezierski
- Centre of New Technologies, University of Warsaw, 02097, Warsaw, Poland
| | - K Koteras
- Centre of New Technologies, University of Warsaw, 02097, Warsaw, Poland
| | - M Domański
- Centre of New Technologies, University of Warsaw, 02097, Warsaw, Poland
| | - P Połczyński
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 02089, Warsaw, Poland
| | - Z Mazej
- Department of Inorganic Chemistry and Technology, Jožef Stefan Institute, 1000, Ljubljana, Slovenia
| | - J Lorenzana
- Institute for Complex Systems (ISC), Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Università di Roma "La Sapienza", 00185, Rome, Italy
| | - W Grochala
- Centre of New Technologies, University of Warsaw, 02097, Warsaw, Poland
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Jezierski D, Grzelak A, Liu X, Pandey SK, Gastiasoro MN, Lorenzana J, Feng J, Grochala W. Charge doping to flat AgF 2 monolayers in a chemical capacitor setup. Phys Chem Chem Phys 2022; 24:15705-15717. [PMID: 35579107 DOI: 10.1039/d2cp00179a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Flat monolayers of silver(II) fluoride, which could be obtained by epitaxial deposition on an appropriate substrate, have been recently predicted to exhibit very strong antiferro-magnetic superexchange and to have large potential for ambient pressure superconductivity if doped to an optimal level. It was shown that AgF2 could become a magnetic glue-based superconductor with a critical superconducting temperature approaching 200 K at optimum doping. In the current work we calculate the optimum doping to correspond to 14% of holes per formula unit, i.e. quite similar to that for oxocuprates(II). Furthermore, using DFT calculations we show that flat [AgF2] single layers can indeed be doped to a controlled extent using a recently proposed "chemical capacitor" setup. Hole doping associated with the formation of Ag(III) proves to be difficult to achieve in the setup explored in this work as it falls at the verge of charge stability of fluoride anions and does not affect the d(x2 - y2) manifold. However, in the case of electron doping, manipulation of different factors - such as the number of dopant layers and the thickness of the separator - permits fine tuning of the doping level (and concomitantly TC) all the way from the underdoped to overdoped regime (in a similar manner to chemical doping for the Nd2CuO4 analogue).
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Affiliation(s)
- Daniel Jezierski
- Center of New Technologies, University of Warsaw, 02089, Warsaw, Poland.
| | - Adam Grzelak
- Center of New Technologies, University of Warsaw, 02089, Warsaw, Poland.
| | - Xiaoqiang Liu
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
| | - Shishir Kumar Pandey
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
| | - Maria N Gastiasoro
- Institute for Complex Systems (ISC), Dipartimento di Fisica, Consiglio Nazionale delle Ricerche, Università di Roma "La Sapienza", 00185, Rome, Italy
| | - José Lorenzana
- Institute for Complex Systems (ISC), Dipartimento di Fisica, Consiglio Nazionale delle Ricerche, Università di Roma "La Sapienza", 00185, Rome, Italy
| | - Ji Feng
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China.,Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China
| | - Wojciech Grochala
- Center of New Technologies, University of Warsaw, 02089, Warsaw, Poland.
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