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Gajda R, Zhang D, Parafiniuk J, Dera P, Woźniak K. Tracing electron density changes in langbeinite under pressure. IUCRJ 2022; 9:146-162. [PMID: 35059218 PMCID: PMC8733888 DOI: 10.1107/s2052252521012628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/27/2021] [Indexed: 06/14/2023]
Abstract
Pressure is well known to dramatically alter physical properties and chemical behaviour of materials, much of which is due to the changes in chemical bonding that accompany compression. Though it is relatively easy to comprehend this correlation in the discontinuous compression regime, where phase transformations take place, understanding of the more subtle continuous compression effects is a far greater challenge, requiring insight into the finest details of electron density redistribution. In this study, a detailed examination of quantitative electron density redistribution in the mineral langbeinite was conducted at high pressure. Langbeinite is a potassium magnesium sulfate mineral with the chemical formula [K2Mg2(SO4)3], and crystallizes in the isometric tetartoidal (cubic) system. The mineral is an ore of potassium, occurs in marine evaporite deposits in association with carnallite, halite and sylvite, and gives its name to the langbeinites, a family of substances with the same cubic structure, a tetrahedral anion, and large and small cations. Single-crystal X-ray diffraction data for langbeinite have been collected at ambient pressure and at 1 GPa using a combination of in-house and synchrotron techniques. Experiments were complemented by theoretical calculations within the pressure range up to 40 GPa. On the basis of changes in structural and thermal parameters, all ions in the langbeinite structure can be grouped into 'soft' (potassium cations and oxygens) and 'hard' (sulfur and magnesium). This analysis emphasizes the importance of atomic basins as a convenient tool to analyse the redistribution of electron density under external stimuli such as pressure or temperature. Gradual reduction of completeness of experimental data accompanying compression did not significantly reduce the quality of structural, electronic and thermal parameters obtained in experimental quantitative charge density analysis.
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Affiliation(s)
- Roman Gajda
- Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, Warszawa 02-089, Poland
| | - Dongzhou Zhang
- APS, University of Chicago, 9700 S. Cass Avenue, Building 434A, Argonne, IL 60439, USA
| | - Jan Parafiniuk
- Institute of Geochemistry, Mineralogy and Petrology, Department of Geology, University of Warsaw, Żwirki i Wigury 93, Warszawa 02-089, Poland
| | - Przemysław Dera
- Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1680 East West Road, Honolulu, Hawaii 96822, USA
| | - Krzysztof Woźniak
- Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, Warszawa 02-089, Poland
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Stachowicz M, Malinska M, Parafiniuk J, Woźniak K. Experimental observation of charge-shift bond in fluorite CaF 2. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2017; 73:643-653. [PMID: 28762974 DOI: 10.1107/s2052520617008617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 06/09/2017] [Indexed: 06/07/2023]
Abstract
On the basis of a multipole refinement of single-crystal X-ray diffraction data collected using an Ag source at 90 K to a resolution of 1.63 Å-1, a quantitative experimental charge density distribution has been obtained for fluorite (CaF2). The atoms-in-molecules integrated experimental charges for Ca2+ and F- ions are +1.40 e and -0.70 e, respectively. The derived electron-density distribution, maximum electron-density paths, interaction lines and bond critical points along Ca2+...F- and F-...F- contacts revealed the character of these interactions. The Ca2+...F- interaction is clearly a closed shell and ionic in character. However, the F-...F- interaction has properties associated with the recently recognized type of interaction referred to as `charge-shift' bonding. This conclusion is supported by the topology of the electron localization function and analysis of the quantum theory of atoms in molecules and crystals topological parameters. The Ca2+...F- bonded radii - measured as distances from the centre of the ion to the critical point - are 1.21 Å for the Ca2+ cation and 1.15 Å for the F- anion. These values are in a good agreement with the corresponding Shannon ionic radii. The F-...F- bond path and bond critical point is also found in the CaF2 crystal structure. According to the quantum theory of atoms in molecules and crystals, this interaction is attractive in character. This is additionally supported by the topology of non-covalent interactions based on the reduced density gradient.
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Affiliation(s)
- Marcin Stachowicz
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, England
| | - Maura Malinska
- Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, Warszawa 02-089, Poland
| | - Jan Parafiniuk
- Institute of Geochemistry, Mineralogy and Petrology, University of Warsaw, Żwirki i Wigury 93, Warszawa 02-089, Poland
| | - Krzysztof Woźniak
- Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, Warszawa 02-089, Poland
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Abstract
Connections established during last century between bond length, radii, bond strength, bond valence and crystal and molecular chemistry are briefly reviewed followed by a survey of the physical properties of the electron density distributions for a variety of minerals and representative molecules, recently generated with first-principles local energy density quantum mechanical methods. The structures for several minerals, geometry-optimized at zero pressure and at a variety of pressures were found to agree with the experimental structures within a few percent. The experimental Si–O bond lengths and the Si–O–Si angle, the Si–O bond energy and the bond critical point properties for crystal quartz are comparable with those calculated for the H6Si2O7disilicic acid molecule, an indication that the bonded interactions in silica are largely short ranged and local in nature. The topology of model experimental electron density distributions for first and second row metal M atoms bonded to O, determined with high resolution and high energy synchrotron single crystal X-ray diffraction data are compared with the topology of theoretical distributions calculated with first principles methods. As the electron density is progressively accumulated between pairs of bonded atoms, the distributions show that the nuclei are progressively shielded as the bond lengths and the bonded radii of the atoms decrease. Concomitant with the decrease in the M–O bond lengths, the local kinetic energy,G(rc), the local potential energy,V(rc), and the electronic energy density,H(rc) =G(rc) +V(rc), evaluated at the bond critical points,rc, each increases in magnitude with the local potential energy dominating the kinetic energy density in the internuclear region for intermediate and shared interactions. The shorter the bonds, the more negative the local electronic energy density, the greater the stabilization and the greater the shared character of the intermediate and shared bonded interactions. In contrast, the local kinetic energy density increases with decreasing bond length for closed shell interactions withG(rc) dominatingV(rc) in the internuclear region, typical of an ionic bond. ...
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Gibbs GV, Downs RT, Cox DF, Rosso KM, Ross NL, Kirfel A, Lippmann T, Morgenroth W, Crawford TD. Experimental bond critical point and local energy density properties determined for Mn-O, Fe-O, and Co-O bonded interactions for tephroite, Mn2SiO4, fayalite, Fe2SiO4, and Co2SiO4 olivine and selected organic metal complexes: comparison with properties calculated for non-transition and transition metal M-O bonded interactions for silicates and oxides. J Phys Chem A 2008; 112:8811-23. [PMID: 18714960 DOI: 10.1021/jp804280j] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bond critical point (bcp) and local energy density properties for the electron density (ED) distributions, calculated with first-principle quantum mechanical methods for divalent transition metal Mn-, Co-, and Fe-containing silicates and oxides are compared with experimental model ED properties for tephroite, Mn 2SiO 4, fayalite, Fe 2SiO 4, and Co 2SiO 4 olivine, each determined with high-energy synchrotron single-crystal X-ray diffraction data. Trends between the experimental bond lengths, R(M-O), (M = Mn, Fe, Co), and the calculated bcp properties are comparable with those observed for non-transition M-O bonded interactions. The bcp properties, local total energy density, H( r c), and bond length trends determined for the Mn-O, Co-O, and Fe-O interactions are also comparable. A comparison is also made with model experimental bcp properties determined for several Mn-O, Fe-O, and Co-O bonded interactions for selected organometallic complexes and several oxides. Despite the complexities of the structures of the organometallic complexes, the agreement between the calculated and model experimental bcp properties is fair to good in several cases. The G( r c)/rho( r c) versus R(M-O) trends established for non-transition metal M-O bonded interactions hold for the transition metal M-O bonded interactions with G( r c)/rho( r c) increasing in value as H( r c) becomes progressively more negative in value, indicating an increasing shared character of the interaction as G( r c)/rho( r c) increases in value. As observed for the non-transition metal M-O bonded interactions, the Laplacian, nabla (2)rho( r c), increases in value as rho( r c) increases and as H( r c) decreases and becomes progressive more negative in value. The Mn-O, Fe-O, and Co-O bonded interactions are indicated to be of intermediate character with a substantial component of closed-shell character compared with Fe-S and Ni-S bonded interactions, which show greater shared character based on the | V( r c)|/ G( r c) bond character indicator. The atomic charges conferred on the transition metal atoms for the three olivines decrease with increasing atomic number from Mn to Fe to Co as the average M-O bond lengths decrease from 2.219 to 2.168 to 2.128 A, respectively.
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Affiliation(s)
- G. V. Gibbs
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - R. T. Downs
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - D. F. Cox
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - K. M. Rosso
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - N. L. Ross
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - A. Kirfel
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - T. Lippmann
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - W. Morgenroth
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
| | - T. D. Crawford
- Departments of Geosciences, Chemical Engineering, and Chemistry, Virginia Tech, Blacksburg, Virginia 24061; Department of Geosciences, University of Arizona, Tucson, Arizona 85721; Chemical and Materials Sciences Division and the W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany; GKSS, Max-Planck-Strasse, D-21502 Geesthacht,
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