Video Experimental Relacionado
Updated: Jul 16, 2026
11:14
Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
La especificidad del sitio y del estado de oxidación da lugar a un control dimensional en los rutenatos de perovskita
Job T Rijssenbeek1, Sylvie Malo, Vincent Caignaert
1Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
Journal of the American Chemical Society
|March 7, 2002
Resumen
Se sintetizó y caracterizó un nuevo rutenato de perovskita, Sr(3) CaRu(2) O(9). Este material exhibe una estructura en capas única y puede transformarse de manera reversible entre las fases 3D y en capas, mostrando versatilidad estructural.
Área de la Ciencia:
- Química del estado sólido.
- Ciencia de los materiales ciencia de los materiales.
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- Los rutenatos de perovskita son de interés por sus diversas propiedades electrónicas y magnéticas.
- El ordenamiento del sitio B en las perovskitas influye en las características estructurales y físicas.
Objetivo del estudio:
- Para sintetizar y determinar la estructura cristalina de un nuevo 2:1 B-sitio ordenado perovskita rutenato, Sr(3) CaRu(2) O(9).
- Investigar las transformaciones estructurales y la versatilidad química de este nuevo material.
Principales métodos:
- Difracción de rayos X en polvo por difracción de rayos X.
- La difracción de neutrones es la difracción de neutrones.
- La difracción de los electrones por difracción.
- Reducción química y oxidación.
Principales resultados:
- Se sintetizó y se determinó su estructura, revelando un apilamiento único de capas de CaO6 y RuO6.
- El compuesto presenta una unidad de repetición [-Ru-Ru-Ca-] a lo largo de direcciones pseudocúbicas.
- Sr(3) CaRu(2) O(9) puede ser reducido a una fase de Ruddlesden-Popper en capas (Sr(1.5) Ca(0.5) RuO(4)) y posteriormente re-oxidado a la estructura original.
Conclusiones:
- Sr(3) CaRu(2) O(9) representa un nuevo tipo de estructura en los rutenatos de perovskita, incorporando Ru(V) con d(3) electrones.
- La transformación reversible entre las estructuras 3D y las estructuras en capas destaca la significativa versatilidad estructural que ofrece el sistema Sr-Ca-Ru-O.
Videos de Conceptos Relacionados
02:42Ionic Crystal Structures
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...
04:08Determining the pH of Salt Solutions
The pH of a salt solution is determined by its component anions and cations. Salts that contain pH-neutral anions and the hydronium ion-producing cations form a solution with a pH less than 7. For example, in ammonium nitrate (NH4NO3) solution, NO3− ions do not react with water whereas NH4+ ions produce the hydronium ions resulting in the acidic solution. In contrast, salts that contain pH-neutral cations and the hydroxide ion-producing anions form a solution with a pH greater than 7. For...
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
03:46Qualitative Analysis
For solutions containing mixtures of different cations, the identity of each cation can be determined by qualitative analysis. This technique involves a series of selective precipitations with different chemical reagents, each reaction producing a characteristic precipitate for a specific group of cations. Metal ions within a group are further separated by varying the pH, heating the mixture to redissolve a precipitate, or adding other reagents to form complex ions.
For instance, group IV...
For instance, group IV...
01:19Ionic Strength: Effects on Chemical Equilibria
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary cation—the calcium...
In this solution, the primary cation—the calcium...
01:19Acid Mine Drainage
Mining activities that disturb sulfide-rich rocks, particularly those containing pyrite (FeS₂), initiate a cascade of geochemical and microbiological processes with serious environmental implications. When exposed to air and water, pyrite undergoes oxidation, releasing sulfate, ultimately forming sulfuric acid and mobilizing heavy metals into surrounding water systems. This phenomenon, known as acid mine drainage (AMD), results in low pH waters laden with toxic elements that threaten aquatic...