Atomic-Scale Understanding of Structure and Properties of Complex Pyrophosphate Crystals by First-Principles Calculations
| Autor: | K. Brouzi, Hamid Ez-Zahraouy, Mohamed Harcharras, Redouane Khaoulaf, Wai-Yim Ching, Puja Adhikari |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
optical properties
Pyrophosphate Materials science 02 engineering and technology Electronic structure mechanical properties 010402 general chemistry 01 natural sciences Atomic units lcsh:Technology Metal Crystal lcsh:Chemistry chemistry.chemical_compound Molecule General Materials Science Instrumentation lcsh:QH301-705.5 Fluid Flow and Transfer Processes Hydrogen bond lcsh:T Process Chemistry and Technology General Engineering 021001 nanoscience & nanotechnology electronic structure lcsh:QC1-999 0104 chemical sciences Computer Science Applications Crystallography chemistry lcsh:Biology (General) lcsh:QD1-999 lcsh:TA1-2040 visual_art first-principles calculations visual_art.visual_art_medium Density functional theory 0210 nano-technology lcsh:Engineering (General). Civil engineering (General) lcsh:Physics |
| Zdroj: | Applied Sciences, Vol 9, Iss 5, p 840 (2019) Applied Sciences Volume 9 Issue 5 |
| ISSN: | 2076-3417 |
| Popis: | The electronic structure and mechanical and optical properties of five pyrophosphate crystals with very complex structures are studied by first principles density functional theory calculations. The results show the complex interplay of the minor differences in specific local structures and compositions can result in large differences in reactivity and interaction that are rare in other classes of inorganic crystals. These are discussed by dividing the pyrophosphate crystals into three structural units. H2P2O7 is the most important and dominating unit in pyrophosphates. The other two are the influential cationic group with metals and water molecules. The strongest P-O bond in P2O5 is the strongest bond for crystal cohesion, but O-H and N-H bonds also play an important part. Different type of bonding between O and H atoms such as O-H, hydrogen bonding, and bridging bonds are present. Metallic cations such as Mg, Zn, and Cu form octahedral bonding with O. The water molecule provides the unique H∙∙∙O bonds, and metallic elements can influence the structure and bonding to a certain extent. The two Cu-containing phosphates show the presence of narrow metallic bands near the valence band edge. All this complex bonding affects their physical properties, indicating that fundamental understanding remains an open question. |
| Databáze: | OpenAIRE |
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