Related Experiment Video
Updated: Jun 6, 2026

07:14
Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers
Published on: May 12, 2023
The shortest metal-metal bond
1Lehrstuhl Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany.
Summary
Researchers synthesized a stable chromium bimetallic complex with a record-shortest metal-metal bond, achieving a formal quintuple bond. This breakthrough advances the field of multiple metal-metal bonding in stable molecules.
Area of Science:
- Inorganic Chemistry
- Organometallic Chemistry
- Materials Science
Background:
- The field of stable bimetallic complexes with high-order metal-metal bonds is rapidly developing.
- Ligand design is crucial for tuning metal-metal bond length and strength.
- Theoretical expectations suggest higher bond orders correlate with shorter bond lengths.
Purpose of the Study:
- To synthesize and isolate stable bimetallic complexes featuring formally quintuply bonded transition metals.
- To investigate the relationship between metal-metal bond order and bond length.
- To achieve the shortest possible metal-metal bond distance in a stable molecule.
Main Methods:
- Synthesis of novel chromium homo-bimetallic complexes.
- Isolation and characterization of the resulting bimetallic compound.
- Determination of the metal-metal bond length and assignment of formal bond order.
Main Results:
- Successful synthesis and isolation of a stable chromium homo-bimetallic complex.
- Achieved a chromium-chromium (Cr-Cr) bond length of 1.7293(12) Å.
- Assigned a formal bond order of five to the Cr-Cr bond, representing the shortest metal-metal bond in a stable molecule to date.
Conclusions:
- The synthesized chromium complex establishes a new record for the shortest metal-metal bond in a stable molecule.
- This work demonstrates the feasibility of achieving and stabilizing high-order (quintiple) metal-metal bonds.
- Further shortening of metal-metal bonds may be possible in future research.
More Related Videos
Related Concept Videos
Bonding in Metals
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
Chemical Bonds
Atoms participate in a chemical bond formation to acquire a completed valence-shell electron configuration similar to that of the noble gas nearest to it in atomic number. Ionic, covalent, and metallic bonds are some of the important types of chemical bonds. Bond energy and bond length determine the strength of a chemical bond.
Types of Chemical Bonds
An ionic bond is formed due to electrostatic attraction between cations and anions. Often, the ions are formed by the transfer of electrons from...
Types of Chemical Bonds
Chemical bonding theories were pioneered by American chemist Gilbert N. Lewis. He developed a model called the Lewis model to explain the type and formation of different bonds. Chemical bonding is central to chemistry; it explains how atoms or ions bond together to form molecules. It explains why some bonds are strong and others are weak, or why one carbon bonds with two oxygens and not three; why water is H2O and not H4O.
Types of Chemical Bonds
Chemical bonding theories were pioneered by American chemist Gilbert N. Lewis. He developed a model called the Lewis model to explain the type and formation of different bonds. Chemical bonding is central to chemistry; it explains how atoms or ions bond together to form molecules. It explains why some bonds are strong and others are weak, or why one carbon bonds with two oxygens and not three; why water is H2O and not H4O.
Bond Energies and Bond Lengths
Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, that is, the energy necessary to separate the bonded atoms. Separating any pair of bonded atoms requires energy — the stronger a bond, the greater the energy required to break it.
Valence Bond Theory
Overview of Valence Bond Theory

