Alkali Metal Decorated Planar Tetracoordinate Hydrogen
Kangkan Sarmah1, Amlan Jyoti Kalita1, Ankur K Guha1
1Advanced Computational Chemistry Centre, Cotton University, Panbazar, Guwahati, Assam, India 781001.
Inorganic Chemistry
|December 7, 2023
Summary
Researchers report the first planar tetracoordinate hydrogen atom (ptH) in a Li₄H₄⁻ cluster. This novel structure is stabilized by multicenter bonding and electrostatic attraction, challenging previous assumptions about hydrogen
Area of Science:
- Quantum Chemistry
- Computational Chemistry
- Materials Science
Background:
- Planar tetracoordinate atoms are well-documented, but hydrogen has remained elusive.
- Hydrogen's propensity for multicenter bonding complicates achieving planar coordination.
Purpose of the Study:
- To synthesize and characterize the first planar tetracoordinate hydrogen atom (ptH).
- To investigate the bonding and stability of this novel structure in a Li₄H₄⁻ cluster.
Main Methods:
- Computational modeling and quantum chemical calculations.
- Analysis of bonding characteristics and charge distribution.
- Dynamic stability simulations.
Main Results:
- The first ptH was identified in the global minimum of a C₂ symmetric Li₄H₄⁻ cluster.
- The central hydrogen atom is stabilized by multicenter bonding with four lithium atoms.
- Natural charge analysis indicates a hydride-like hydrogen attracted to positively charged lithium centers, stabilized by electrostatic forces.
Conclusions:
- The ptH structure in Li₄H₄⁻ is dynamically stable and predicted to be observable in the gas phase.
- Aromaticity does not contribute to the stabilization of this ptH configuration.
- Replacing lithium with heavier alkali metals like sodium results in a less stable, non-global minimum planar structure.
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