“crystal-field theory”的概念、定义、翻译、参考文献-科学参考

crystal-field theory

Physics

A theory of the electronic structures of inorganic complexes, in which the complex is assumed to consist of a central metal atom or ion surrounded by ligands that are ions. For example, the complex [PtCl₄]²⁻ is thought of as a Pt²⁺ ion surrounded by four Cl⁻ ions at the corners of a square. The presence of these ions affects the energies of the d-orbitals, causing a splitting of energy levels. The theory can be used to explain the spectra of complexes and their magnetic properties. Ligand-field theory is a development of crystal-field theory in which the overlap of orbitals is taken into account. Crystal-field theory was initiated in 1929 by Hans Bethe and extensively developed in the 1930s.

Chemistry

A theory of the electronic structures of inorganic complexes, in which the complex is assumed to consist of a central metal atom or ion surrounded by ligands that are ions. For example, the complex [PtCl₄]²⁻ is thought of as a Pt²⁺ ion surrounded by four Cl⁻ ions at the corners of a square. The presence of these ions affects the energies of the d-orbitals, causing a splitting of energy levels. The theory can be used to explain the spectra of complexes and their magnetic properties. Crystal-field theory was initiated in 1929 by the German-born US physicist Hans Albrecht Bethe (1906–2005) and extensively developed in the 1930s. Ligand-field theory extended crystal-field theory by combining it with molecular-orbital theory, with the effect that covalent bonding between transition metal atoms and ligands can be taken into account. This can also be achieved by combining crystal-field theory with valence-bond theory.

Geology and Earth Sciences

A theory describing the behaviour of elements with partly filled d- or f-orbitals. In geochemistry it is particularly concerned with the crystal-field (ligand-field) effects on the first transition metal ions, i.e. Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. If the anions surrounding a cation are considered as point charges then the electrostatic interactions between them will vary according to: (a) ionic distance; (b) the strength of the charge; and (c) the coordination number (how anions are distributed around the cation). Some of the five d-orbitals will have maximum electron density nearer to the anion than others. Interactions between cation and anion will affect the energies of the d-orbitals and cause a separation of energy levels between orbitals (crystal-field splitting).

单词	crystal-field theory
释义	crystal-field theory Physics A theory of the electronic structures of inorganic complexes, in which the complex is assumed to consist of a central metal atom or ion surrounded by ligands that are ions. For example, the complex [PtCl₄]²⁻ is thought of as a Pt²⁺ ion surrounded by four Cl⁻ ions at the corners of a square. The presence of these ions affects the energies of the d-orbitals, causing a splitting of energy levels. The theory can be used to explain the spectra of complexes and their magnetic properties. Ligand-field theory is a development of crystal-field theory in which the overlap of orbitals is taken into account. Crystal-field theory was initiated in 1929 by Hans Bethe and extensively developed in the 1930s. Chemistry A theory of the electronic structures of inorganic complexes, in which the complex is assumed to consist of a central metal atom or ion surrounded by ligands that are ions. For example, the complex [PtCl₄]²⁻ is thought of as a Pt²⁺ ion surrounded by four Cl⁻ ions at the corners of a square. The presence of these ions affects the energies of the d-orbitals, causing a splitting of energy levels. The theory can be used to explain the spectra of complexes and their magnetic properties. Crystal-field theory was initiated in 1929 by the German-born US physicist Hans Albrecht Bethe (1906–2005) and extensively developed in the 1930s. Ligand-field theory extended crystal-field theory by combining it with molecular-orbital theory, with the effect that covalent bonding between transition metal atoms and ligands can be taken into account. This can also be achieved by combining crystal-field theory with valence-bond theory. Geology and Earth Sciences A theory describing the behaviour of elements with partly filled d- or f-orbitals. In geochemistry it is particularly concerned with the crystal-field (ligand-field) effects on the first transition metal ions, i.e. Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. If the anions surrounding a cation are considered as point charges then the electrostatic interactions between them will vary according to: (a) ionic distance; (b) the strength of the charge; and (c) the coordination number (how anions are distributed around the cation). Some of the five d-orbitals will have maximum electron density nearer to the anion than others. Interactions between cation and anion will affect the energies of the d-orbitals and cause a separation of energy levels between orbitals (crystal-field splitting).
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