Structural Basis for Metastability in Amorphous Calcium Barium Carbonate (ACBC)
| Autor: | Derk Joester, Saivenkataraman Jayaraman, Karen DeRocher, Wenhao Sun, Gerbrand Ceder, Michael L. Whittaker |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Coordination number chemistry.chemical_element 02 engineering and technology 010402 general chemistry 01 natural sciences Biomaterials metastability chemistry.chemical_compound Engineering Polyamorphism Metastability Electrochemistry Materials polyamorphism Barium 021001 nanoscience & nanotechnology Condensed Matter Physics biomineralization 0104 chemical sciences Electronic Optical and Magnetic Materials Amorphous solid chemistry Chemical physics Chemical Sciences Physical Sciences Carbonate Barium carbonate Density functional theory 0210 nano-technology amorphous calcium-barium carbonate |
| Zdroj: | Advanced Functional Materials, vol 28, iss 2 Whittaker, ML; Sun, W; DeRocher, KA; Jayaraman, S; Ceder, G; & Joester, D. (2018). Structural Basis for Metastability in Amorphous Calcium Barium Carbonate (ACBC). Advanced Functional Materials, 28(2). doi: 10.1002/adfm.201704202. UC Berkeley: Retrieved from: http://www.escholarship.org/uc/item/5n82c16f |
| Popis: | Author(s): Whittaker, ML; Sun, W; DeRocher, KA; Jayaraman, S; Ceder, G; Joester, D | Abstract: Metastable amorphous precursors are emerging as valuable intermediates for the synthesis of materials with compositions and structures far from equilibrium. Recently, it was found that amorphous calcium barium carbonate (ACBC) can be converted into highly barium-substituted “balcite,” a metastable high temperature modification of calcite with exceptional hardness. A systematic analysis ACBC (Ca1-xBaxCO3·1.2H2O) in the range from x = 0–0.5 is presented. Combining techniques that independently probe the local environment from the perspective of calcium, barium, and carbonate ions, with total X-ray scattering and a new molecular dynamics/density functional theory simulations approach, provides a holistic picture of ACBC structure as a function of composition. With increasing barium content, ACBC becomes more ordered at short and medium range, and increasingly similar to crystalline balcite, without developing long-range order. This is not accompanied by a change in the water content and does not carry a significant energy penalty, but is associated with differences in cation coordination resulting from changing carbonate anion orientation. Therefore, the local order imprinted in ACBC may increasingly lower the kinetic barrier to subsequent transformations as it becomes more pronounced. This pathway offers clues to the design of metastable materials by tuning coordination numbers in the amorphous solid state. |
| Databáze: | OpenAIRE |
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