hypervalent molecule造句
例句與造句
- This localization of charge is accommodated by the fact that the terminal ligands are highly electronegative in hypervalent molecules.
- The apparent increased reactivity of hypervalent molecules, contrasted with tetravalent analogues, has also been observed for Grignard reactions.
- Pauling also considered hypervalent molecules, in which main-group elements have apparent valences greater than the maximal of 4 allowed by the octet rule.
- There are, however, some hypervalent molecules in which the 3d level may play a part in the bonding, although this is controversial ( see below ).
- Molecules without an s-orbital lone pair such as PF 5 and SF 6 are described by an extended version of the 3-center 4-electron model ( See hypervalent molecule ).
- It's difficult to find hypervalent molecule in a sentence. 用hypervalent molecule造句挺難的
- For hypervalent molecules, the energy is represented as a combination of VALBOND configurations, which are akin to resonance structures that place three-center four-electron bonds ( 3c4e ) in different ways.
- Single bonds can also be moved in the same way to create resonance structures for hypervalent molecules such as sulfur hexafluoride, which is the correct description according to quantum chemical calculations instead of the common expanded octet model.
- The attempt to actually prepare hypervalent organic molecules began with Hermann Staudinger and Georg Wittig in the first half of the twentieth century, who sought to challenge the extant valence theory and successfully prepare nitrogen and phosphorus-centered hypervalent molecules.
- It can be understood from these experiments that the increased reactivity observed for hypervalent molecules, contrasted with analogous nonhypervalent compounds, can be attributed to the congruence of these species to the hypercoordinated activated states normally formed during the course of the reaction.
- Main-group elements in the third and later rows of the periodic table can form hypercoordinate or hypervalent molecules in which the central main-group atom is bonded to more than four other atoms, such as phosphorus pentachloride, PCl 5, and sulfur hexafluoride, SF 6.
- In the late 1920s and 1930s, Sugden argued for the existence of a two-center one-electron ( 2c-1e ) bond and thus rationalized bonding in hypervalent molecules without the need for expanded octets or ionic bond character; this was poorly accepted at the time.
- This represents an advantage over the simpler harmonic oscillator approximation used by many force fields, and allows the VALBOND method to handle hypervalent molecules and force fields such as CHARMM and UFF to provide a complete functional form that includes also bond stretching, torsions, and non-bonded interactions.
- :: The article about hypervalent molecules has several explanations using more modern theories than the simple " number of electrons in the valance shell " and standard 2-electron valence bonding ( i . e ., the origins of the octet limit for second-period vs expanded-octet via d orbitals for third and beyond ).