Sigma Bond

Strongest type of covalent chemical bond; formed by head-on overlapping between atomic orbitals. Sigma bonding for diatomic molecules (using the language and tools of symmetry groups):σ-bond is symmetrical with respect to rotation about the bond axis
6 articles (0.01 seconds)
Discovery of a stable single-electron covalent bond between two carbon atoms validates a century-old theory
Covalent bonds, in which two atoms are bound together by sharing a pair of electrons, form the scaffolding that underpins the majority of organic compounds. In 1931, the Nobel Laureate Linus Pauling suggested that covalent bonds made from just a single, unpaired electron could exist, but these single-electron bonds would likely be much weaker than a standard covalent bond involving a pair of electrons.
Science & Technology
phys.org
Catalytic disconnection of C–O bonds in epoxy resins and composites - Nature
The authors report a transition-metal-catalysed protocol for recovery of polymer building block bisphenol  A and intact fibres from epoxy composites, demonstrating that chemical recycling approaches for thermoset epoxy resins and composites are achievable.
Science & Technology
www.nature.com
Scientists propose theory of σ bond resonance in flat boron materials
Recently, two-dimensional (2D) boron sheets—borophenes—have drawn great interest from materials scientists because of their similarity to graphene. However, understanding of how the material can be stable in the 2D form is still lacking, mainly due to boron's unique electron-deficient nature.
Science & Technology
phys.org
Physicists discover new rule for orbital formation in chemical reactions
Squeaky, cloudy or spherical—electron orbitals show where and how electrons move around atomic nuclei and molecules. In modern chemistry and physics, they have proven to be a useful model for quantum mechanical description and prediction of chemical reactions. Only if the orbitals match in space and energy can they be combined—this is what happens when two substances react with each other chemically. In addition,…
Science & Technology
phys.org
Photocatalytic synthesis of arylacetic acid via C=C double bond cleavage with carbon dioxide
Alkenes represent one of the most abundant classes of organic molecules, which are available in bulk quantities from petroleum and renewable resources, with various utilization in agrochemistry, pharmacy, and organic materials. Typically, the transformation of alkenes by cleavage of both the σ bond and π bond underpins a range of industrial processes and provides methods for the reconstruction of hydrocarbon…
Science & Technology
phys.org
A fresh look at 1,2,3-cyclohexatriene shows it could be used as a versatile reagent in organic synthesis
A team of chemists at the University of California, Los Angeles has found that the benzene isomer 1,2,3-cyclohexatriene has the potential to be a versatile reagent in organic synthesis. In their study, reported in the journal Nature, Andrew Kelleghan, Ana Bulger, Dominick Witkowski and Neil Garg conducted experiments with the high-energy compound.
Science & Technology
phys.org