1. Effect of Extra-Framework Cations on Negative Linear Compressibility and High-Pressure Phase Transitions: A Study of KCd[Ag(CN) 2 ] 3
- Author
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Arie van der Lee, Jérôme Rouquette, Julien Haines, Jadna Catafesta, Patrick Hermet, Jean-Louis Bantignies, David Maurin, Andrew B. Cairns, Vladimir Dmitriev, Andrew L. Goodwin, Claire Levelut, Inorganic Chemistry Laboratory [Oxford], University of Oxford [Oxford], Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Européen des membranes (IEM), and Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)
- Subjects
Technology ,Phase transition ,Physical and chemical processes ,Materials Science ,Hydrostatic pressure ,Thermodynamics ,Materials Science, Multidisciplinary ,02 engineering and technology ,010402 general chemistry ,Quantum mechanics ,Physical Chemistry ,01 natural sciences ,09 Engineering ,Thermal expansion ,chemistry.chemical_compound ,Negative thermal expansion ,10 Technology ,Phase (matter) ,[CHIM]Chemical Sciences ,Nanoscience & Nanotechnology ,Physical and Theoretical Chemistry ,Bulk modulus ,Science & Technology ,Chemistry, Physical ,CONSTANTS ,Zirconium tungstate ,Lattices ,021001 nanoscience & nanotechnology ,Infrared light ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Chemistry ,General Energy ,chemistry ,Phase transitions ,Physical Sciences ,Compressibility ,Science & Technology - Other Topics ,THERMAL-EXPANSION ,03 Chemical Sciences ,0210 nano-technology - Abstract
International audience; The negative thermal expansion material potassium cadmium dicyanoargentate, KCd[Ag(CN) 2 ] 3 , is studied at high pressure using a combination of X-ray single-crystal diffraction, X-ray powder diffraction, infrared and Raman spectroscopy, and density functional theory calculations. In common with the isostructural manganese analogue, KMn[Ag(CN) 2 ] 3 , this material is shown to exhibit very strong negative linear compressibility (NLC) in the crystallographic c direction due to structure hinging. We find increased structural flexibility results in enhanced NLC and NTE properties, but this also leads to two pressure-induced phase transitionsto very large unit cells involving octahedral tilting and shearing of the structurebelow 2 GPa. The presence of potassium cations has an important effect on the mechanical and thermodynamic properties of this family, while the chemical versatility demonstrated here is of considerable interest to tune unusual mechanical properties for application. ■ INTRODUCTION Materials where external stimuli induces an anomalous response, such as expansion upon cooling (negative thermal expansion, NTE 1−3) or on application of hydrostatic pressure (negative linear compressibility, NLC 4,5), have recently received considerable attention. These materials that "break the rules"as a result of specific, and therefore rare, elastic anomalies 6−8 are curious from a fundamental point of view but might also be revolutionary for a range of technologies including interferometric pressure sensors, pressure-controlled or pressure-sensitive electronic devices, and smart actua-tion. 2,4,9−11 The ability to design materials with unusual properties is therefore a key focus of the field: can we understand these elastic anomalies so that we can tune the magnitude and/or range of negative responses? Negative thermal expansion may occur in one, two, or all principal directions without violating thermodynamics. 12,13 Thus, for example, the volume coefficient of thermal expansion (CTE), () V V V T p 1 α = ∂ ∂ , takes large negative values in zirconium tungstate ZrW 2 O 8 and zinc(II) cyanide Zn(CN) 2 over large temperature ranges. 14 Under hydrostatic pressure, however, volume must always reduce and so the volume compressibility (() K V V V p T 1 = − ∂ ∂ , conventionally formulated as the bulk modulus, B = (K V) −1), must be definite and positive. 15 Expansion under pressure can occur in one or two directions, as long as this is coupled to volume reduction. 5,12,16 Therefore, negative linear compressibility (NLC)the expansion in one principal direction of a material under hydrostatic pressureis conceptually and empirically related to linear-NTE. In both cases, anomalous response relies on mechanical anisotropy. The so-called "wine-rack" model is often invoked where mechanical hinging allows linear expansion coupled to volume reduction on increasing pressure or decreasing temperature. 5,8 Attention in this field has focused on a class of materials known as coordination polymers (CPs), in particular due to the very large magnitude of responses found in comparison to conventional oxide-based materials. 7 Examples that show large NTE and NLC include cyanide frameworks such as Ag 3 [Co-(CN) 6 ] (refs 17 and 18), KMn[Ag(CN) 2 ] 3 (refs 19 and 20), Zn[Au(CN) 2 ] 2 (refs 21 and 22), and metal−organic frameworks 23 (MOFs) such as MIL-53 (ref 24), UTSA-16 (ref 25), ZAG-4 (ref 26), and [NH 4 ][Zn(HCOO) 3 ] (ref 27). In many cases, mechanical response can be predicted in these systems by considering the framework as a set of rigid connectors and hinges, sodepending on geometry and topologyNTE or
- Published
- 2020