Related Experiment Video
Updated: Jun 5, 2026
05:15
An Aptamer-based Sensor for Unchelated Gadolinium(III)
Published on: January 9, 2017
Tetra-μ-2,5-difluoro-benzoato-bis-[(2,2'-bipyridine)(2,5-difluoro-benzoato)gadolinium(III)]
Acta Crystallographica. Section E, Structure Reports Online
|January 5, 2011
Abstract:
In the centrosymmetric title compound, [Gd(2)(C(7)H(3)F(2)O(2))(6)(C(10)H(8)N(2))(2)], the asymmetric unit comprises one cation chelated by two 2,5-difluoro-benzoate and one 2,2'-bipyridine. Two cations are linked into dimers via three bridging carboxyl-ate groups from three 2,5-difluoro-benzoic acid units. The Gd(III) ion is nine-coord-inated by seven O atoms and two N atoms.
Related Concept Videos
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...