Related Experiment Video
Updated: Apr 4, 2026

Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
catena-Poly[[diaqua-strontium]-bis-(μ-quinoline-3-carboxyl-ato)]
Abstract:
The title compound, [Sr(C(10)H(6)NO(2))(2)(H(2)O)(2)](n), contains an eight-coordinate Sr(II) ion displaying a distorted square-anti-prismatic geometry, two quinoline-3-carboxyl-ate ligands and two terminal water mol-ecules. The Sr(II) atom is surrounded by six carboxyl-ate O atoms from four separate quinoline-3-carboxyl-ate ligands and two O atoms from two coordinated water mol-ecules. The bridging carboxyl-ate O atoms [Sr-O = 2.498 (3) and 2.495 (3) Å] link Sr(II) atoms, forming a chain substructure extending along the c axis. The chains are linked by O-H⋯N and O-H⋯O hydrogen bonds, giving a three-dimensional framework structure.
Related Concept Videos
Coordination Compounds and Nomenclature
Coordination Number and Geometry
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Valence Bond Theory
Complexation Equilibria: Overview
The equilibrium constant of the complexation reaction is represented as the formation constant...
Complexometric Titration: Ligands

