Video Experimental Relacionado
Updated: Oct 1, 2025
08:30
Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells
Published on: March 19, 2017
16.8K
Perovskita cúbica débil en el manto de la Tierra
J Immoor1, L Miyagi2, H-P Liermann3
1Bayerisches Geoinstitut (BGI), University of Bayreuth, Bayreuth, Germany.
Nature
|March 10, 2022
Resumen
La perovskita de silicato de calcio cúbico (CaSiO3) es una fase débil del manto inferior. Su baja resistencia y viscosidad pueden gobernar la dinámica de la losa de subducción y explicar las anomalías sísmicas.
Área de la Ciencia:
- La geofísica
- Física de los minerales
- Geoquímica de alta presión
Sus antecedentes:
- La perovskita cúbica CaSiO3 se forma en la corteza oceánica subducida a ~ 550 km de profundidad.
- Sus propiedades reológicas en el manto inferior siguen siendo poco conocidas.
Objetivo del estudio:
- Para investigar la resistencia plástica y el comportamiento reológico de la perovskita cúbica CaSiO3.
- Determinar su papel en la dinámica de la placa de subducción y la estructura del manto inferior.
Principales métodos:
- Mediciones de la resistencia plástica de la perovskita cúbica de CaSiO3.
- Simulaciones a altas presiones y temperaturas que simulan las condiciones del manto inferior (hasta ~ 1200 km de profundidad).
Principales resultados:
- La perovskita cúbica CaSiO3 es significativamente más débil que la bridgmanita y la ferropericlasa a temperaturas más bajas del manto.
- Su resistencia y viscosidad son sustancialmente más bajas que otras fases principales del manto inferior.
- Identificado como la fase potencialmente más débil en el manto inferior.
Conclusiones:
- La perovskita cúbica débil CaSiO3 probablemente gobierna la dinámica de la losa de subducción.
- Proporciona un mecanismo para separar la corteza oceánica del manto.
- Puede explicar las regiones de baja velocidad sísmica en el manto inferior superior y en el límite núcleo-manto.
Videos de Conceptos Relacionados
02:42Ionic Crystal Structures
15.4K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
15.4K
02:37Metallic Solids
19.4K
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
19.4K
02:33Lattice Centering and Coordination Number
10.2K
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1.
Types of Unit Cells
Imagine taking a large number of identical...
Types of Unit Cells
Imagine taking a large number of identical...
10.2K
02:58Crystal Field Theory - Octahedral Complexes
28.1K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
28.1K
02:54Molecular and Ionic Solids
18.3K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
18.3K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
45.0K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
45.0K