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This bonding arrangement is indicated by a short C–N distance and the coplanarity of the NCS 2 core as well as the atoms attached to N. [6] Main resonance structures of a dithiocarbamate anion. Because of the pi-donation from nitrogen, dithiocarbamates are more basic than structurally related anions such as dithiocarboxylates and xanthates .
The synthesis of (E)-4-iodo-3-methylbut-3-en-1-ol [12] shown below is a typical application of this reaction: For terminal alkynes, the reaction generally proceeds with good regioselectivity (>90:10 rr) and complete syn selectivity, even in the presence of propargylic or homopropargylic heteroatom substituents.
Molecular orbital theory revolutionized the study of chemical bonding by approximating the states of bonded electrons – the molecular orbitals – as linear combinations of atomic orbitals (LCAO). These approximations are made by applying the density functional theory (DFT) or Hartree–Fock (HF) models to the Schrödinger equation.
Structures of phosphaaluminirene [9] (1) and distonic radical ion [10] (2). IBO analysis has been employed in main group chemistry to elucidate oftentimes non-trivial electronic structure. The bonding of phosphaaluminirenes was, for example, investigated showing a 3-center-2π-electron bond of the AlCP cycle. [11]
A valence bond structure resembles a Lewis structure, but when a molecule cannot be fully represented by a single Lewis structure, multiple valence bond structures are used. Each of these VB structures represents a specific Lewis structure. This combination of valence bond structures is the main point of resonance theory.
Chemist Linus Pauling first developed the hybridisation theory in 1931 to explain the structure of simple molecules such as methane (CH 4) using atomic orbitals. [2] Pauling pointed out that a carbon atom forms four bonds by using one s and three p orbitals, so that "it might be inferred" that a carbon atom would form three bonds at right angles (using p orbitals) and a fourth weaker bond ...
The enthalpy data show that AlMe 3 is a hard acid and its acid parameters in the ECW model are E A =8.66 and C A = 3.68. These adducts, e.g. the complex with the tertiary amine DABCO , are safer to handle than TMA itself.
What is in most respects a purely covalent structure can support metallic delocalization of electrons; metallic carbon nanotubes are one example. Transition metals and intermetallic compounds based on transition metals can exhibit mixed metallic and covalent bonding, [ 6 ] resulting in high shear strength, low ductility, and elevated melting ...