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Pentagonal planar molecules

IS the first example of a pentagonal planar inorganic ion (Fig. I7.3g)., It can be rationalized in terms of five bonding pairs to fiuorine atoms in a plane with a lone pair above and below the plane. The lone pairs appear to be "locked in to the axial positions as the molecule is rot fluxiona). as is the isoelectronic XcF6. [Pg.951]

Furan, thiophene, and pyrrole, the three heterocycles parent to all the others of this class, have a pentagonal planar structure. Bond lengths and angles are quantities of relevance to our discussion. The values reported below have been chosen because they are more comparable having been determined by the same authors11-13 using the same procedure. In the valence bond description, these molecules... [Pg.237]

The XeF5 anion has an unusual pentagonal planar structure that is much more rigid than the planar equatorial fluorines in the fluxional IF7 molecule. The rigidity is attributed to increased repulsions from the Xe electron pairs.16... [Pg.592]

E8.11 Using VSEPR theory we can determine that XeFs" has a pentagonal planar molecular geometry, so all five of the F atoms are magnetically equivalent and thus the molecule shows a single F resonance. Approximately 25% of the Xe is present as Xe, which has I = 1/2, and in this case the resonance is split into a doublet. The final result is a composite two lines each of 12.5% intensity from the F coupled to the Xe, and one line of 75% intensity for the remainder. [Pg.104]

The second example of a pentagonal planar XYs-type molecule is the IFs " ion, which is isoelectronic with the XeFs ion. It was obtained as the N(CH3)4 salt from the reaction of N(CH3)4lF4 and N(CH3)4F in CH3CN solution, and the IR and Raman spectra were assigned under symmetry [1176]. [Pg.221]

An XYs molecule may adopt a trigonal bipyramidal, a tetragonal pyramidal or a planar-pentagonal structure. The trigonal bipyramidal, XY5 (e.g. SF5 or BrFs), shows six normal infrared-active vibrations, while planar-pentagonal XY5 molecules (e.g. XeFs") show three infrared-active normal vibrations. [Pg.102]

The other approach used to form more planar n-extended acceptor molecules involves the use of heterocyclic systems. Despite the steric crowding introduced by ring fusion, it has been shown experimentally that planar molecules are formed when pentagonal heterocyclic systems bearing no peri hydrogen atoms are fused to the TCNQ ring. [Pg.31]

The molecule XeF52 is the only known example of the AX5E2 type of molecule. It has the expected planar pentagonal geometry based on the pentagonal bipyramid with a lone pair in each of the less-crowded axial positions and an Xe—F bond length of 201 pm (Figure 9.27). [Pg.255]

An interesting structural feature of [Fe(dapsox)(H20)2l is its pentagonal-bipyramidal (PBP) geometry with kinetically labile solvent molecules coordinated in the axial positions and the completely planar pentadentate chelate in the equatorial plane, which generally facilitates easy access of nucleophiles to the metal center without any steric hindrance above and below the pentadentate plane. [Pg.75]

Some examples of molecules having inversion centers are octahedral AB6, planar AB4, planar and trans AB2C2, linear ABA, ethylene, and benzene. Two examples of otherwise fairly symmetrical molecules that do not have centers of inversion are C5H5" (plane pentagon) and tetrahedral AB4 (even though A is at the center and B s come in even numbers). [Pg.22]


See other pages where Pentagonal planar molecules is mentioned: [Pg.252]    [Pg.14]    [Pg.324]    [Pg.939]    [Pg.252]    [Pg.831]    [Pg.220]    [Pg.220]    [Pg.237]    [Pg.341]    [Pg.41]    [Pg.43]    [Pg.63]    [Pg.98]    [Pg.831]    [Pg.66]    [Pg.78]    [Pg.36]    [Pg.113]    [Pg.304]    [Pg.1227]    [Pg.107]    [Pg.67]    [Pg.135]    [Pg.572]    [Pg.174]    [Pg.322]    [Pg.130]    [Pg.140]    [Pg.628]    [Pg.77]    [Pg.56]    [Pg.1212]   
See also in sourсe #XX -- [ Pg.45 ]

See also in sourсe #XX -- [ Pg.51 ]




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