Related Experiment Video
Updated: Mar 24, 2026

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Stabilization of 3d Transition Metal Hydrido Complexes in SrH2Mg2[Co(I)H5], BaH2Mg5[Co(-I)H4]2, and RbH2Mg5[Co(-I)H4
Henrik Fahlquist1, David Moser1, Dag Noréus1
1Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden.
Abstract:
A combined study using neutron diffraction, inelastic neutron scattering, and first-principles calculations describe cobalt with a very low formal oxidation state of (-I) in a slightly distorted tetrahedral Co(-I)H4-complex in BaH2Mg5[Co(-I)H4]2 and in the structurally related RbH2Mg5[Co(-I)H4 Ni(0)H4]. This indicates that the electron "back donating" effect via the polarizable hydride ions to the counterions in the solid state hydrides, can be compared to more conventional "back bonding" able to reduce the oxidation state down to -I. The hydrides were synthesized by hot sintering of transition metal powders with corresponding binary alkali- and alkaline earth hydrides. In the similarly synthesized SrH2Mg2[Co(I)H5], cobalt is formally + I-valent, showing a high sensitivity to differences in the counterion framework, which can also influence electrical properties.
More Related Videos
12:30Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework
Published on: April 9, 2018
09:45Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
Related Concept Videos
Complexation Equilibria: Factors Influencing Stability of Complexes
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Complexation Equilibria: The Chelate Effect
Valence Bond Theory
Crystal Field Theory - Octahedral Complexes
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...
Complexometric Titration: Ligands