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Lewis structures cations

All the following compounds are charactenzed by ionic bonding between a group I metal cation and a tetrahedral anion Wnte an appropriate Lewis structure for each anion remembenng to specify formal charges where they exist... [Pg.50]

Most stable Lewis structure of benzyl cation... [Pg.445]

Although Lewis structures of this type are not entirely adequate descriptions of the structure of the excited states, they do correspond to the MO picture by indicating distortion of chaige and the presence of polar or radical-like centers. The excited states are much more reactive than the corresponding ground-state molecules. In addition to the increased energy content, this high reactivity is associated with the presence of half-filled orbitals. The two SOMO orbitals in the excited states have enhanced radical, cationic, or anionic character. [Pg.754]

When we say cycloheptatriene is not aromatic but cycloheptatrienyl cation is, we are not comparing the stability of the two to each other. Cycloheptatriene is a stable hydrocarbon but does not possess the special stability required to be called aromatic. Cycloheptatrienyl cation, although aromatic, is still a carbocation and reasonably reactive toward nucleophiles. Its special stability does not imply a rock-like passivity, but rather a much greater ease of formation than expected on the basis of the Lewis structure drawn for it. A number of observations indicate that cycloheptatrienyl cation is far-more stable than most other car bocations. To emphasize its aromatic nature, chemists often write the structure of cycloheptatrienyl cation in the Robinson circle-in-a-ring style. [Pg.457]

Draw Lewis structures for allyl cation. Where is the positive charge Examine atomic charges as well as the electrostatic potential map for localized and delocalized forms of allyl cation. Which carbon (s) carries the charge in each ... [Pg.40]

Draw Lewis structures for methyl anion, ammonia and hydronium cation. How many electrons are left over in each after all bonds have been made Display and compare electron density surfaces for methyl anion, ammonia and hydronium cation. Which is the smallest molecule Which is the largest Rationalize your observation. (Hint Compare the number of electrons in each molecule, and the nuclear charge on the central atom in each molecule.)... [Pg.43]

Draw a Lewis structure (or series of Lewis structures) foi 2-norbornyl cation which adequately describes its geometry, charge distribution and bond density surface, Relate this structure to your description of 3-methyl-1-butyl cation. [Pg.44]

Nucleophiles can also act as acids and bases, and this behavior substantially alters their nucleophilicity. At pH 5, trimethylamine exists mainly as its conjugate acid, trimethylammonium cation. First draw a Lewis structure, and then examine the electrostatic potential for trimethylammonium ion. On the basis of the map, which is the better nucleophile, the cation or the corresponding neutral amine At pH 12, phenol exists mainly as its conjugate base, phenoxide anion. First draw a Lewis structure (or series of Lewis structures), and then examine the electrostatic potential map for phenoxide anion. Which is the better nucleophile, phenoxide or phenol ... [Pg.87]

Draw Lewis structures for the possible carbocations resulting from protonation of the double bond in 3-methyl-1-butene, and decide which is favored. (Check your result using available energy data for C5H11 carbocations.) What would be the product of bromide addition to the more stable cation Is this the observed product ... [Pg.110]

The first step in the addition of an electrophile such as HBr to an alkyne involves protonation and subsequent formation of an intermediate vinyl cation. Where does propyne protonate Compare energies of 1-methylvinyl and 2-methylvinyl cations. Which is more stable Why Measure CC bond distance in the more stable cation. Does the cation incorporate a full triple bond (as in propyne) or a double bond (as in propene). Examine atomic charges and electrostatic potential maps to locate the positive charge in the two cations. Is the more stable ion the one in which the charge is better delocalized Use the charges together with information about the ions geometry to draw Lewis structures (or a series of Lewis structures) for 1-methylvinyl and 2-methylvinyl cations. [Pg.116]

Use geometries, electrostatic potential maps and spin densities to help you draw Lewis structures for butanal radical cation, the transition state and product. Where is the positive charge and the unpaired electron in each Is the positive charge (the unpaired electron) more or less delocalized in the transition state than in the reactant In the product ... [Pg.270]

In 1999, Karl Christe synthesized and characterized a salt that contained the N,+ cation, in which the five N atoms are connected in a long chain. This cation is the first allnitrogen species to be isolated in more than 100 years. Draw the most important Lewis structure for this ion, including all equivalent resonance structures. Calculate the formal charges on all atoms. [Pg.212]

A Lewis structure shows all valence electrons and only valence electrons, so a correct count of valence electrons is essential. Recall from Section 8- that the number of valence electrons of an atom can be found from its position in the periodic table. Add the contributions from all atoms to obtain a total count of valence electrons. If the species is an anion, add one electron for each negative charge if the species is a cation, subtract one electron for each positive charge. [Pg.587]

A The Lewis structure for the cation, the anion, and the compound follows the explanation. [Pg.202]

B Below each explanation are the Lewis structures for the cation, for the anion, and for the compound. [Pg.202]

A plausible Lewis structure for the nitrosonium cation, NO+ is drawn below ... [Pg.204]

A Following the strategy outlined in the textbook, we begin by drawing a plausible Lewis structure for the cation in question. In this case, the Lewis structure must contain 20 valence electrons. The skeletal structure for the cation has a chlorine atom, the least electronegative element present, in the central position. Next we join the terminal chlorine and fluorine atoms to the central chlorine atom via single covalent bonds and then complete the octets for all three atoms. [Pg.233]

However, it is entirely possible that the final cation M+ achieves a well-localized Lewis-structure form, but with different NBOs than those of the neutral species. This is the case for three of the four ions considered above (CO+, N2+, H20+), whichleads to high %p( L) values as shown in Table 3.7. For each of the equilibrium... [Pg.121]

The N2 molecule exhibits the expected s-rich hybridization in nN and p-rich hybridization in onn. In other respects its Lewis structure appears quite ordinary, exhibiting the expected similarities to the isoelectronic CO molecule. The a spin set of the cation is also unexceptional. [Pg.123]

Despite the extensive reorganization of individual NBOs, the final cation exhibits a well-localized Lewis structure (%p(L) = 99.92%), which is even more Lewis-like than that of the parent neutral species (%p(L) = 99.89%). [Pg.124]

It is also possible to write a Lewis structure for polyatomic anions or cations. The N - A = S rule can be used, but for an anion extra electrons equal to the magnitude of the negative charge must be added to the electrons available. If the ion is a cation, you will need to subtract number of electrons equal to the charge. [Pg.135]

When using the N - A = S rule in writing Lewis structures, be sure you add electrons to the A term for a polyatomic anion, and subtract electrons for a polyatomic cation. [Pg.158]

Clay minerals behave like Bronsted acids, donating protons, or as Lewis acids (Sect. 6.3), accepting electron pairs. Catalytic reactions on clay surfaces involve surface Bronsted and Lewis acidity and the hydrolysis of organic molecules, which is affected by the type of clay and the clay-saturating cation involved in the reaction. Dissociation of water molecules coordinated to surface, clay-bound cations contributes to the formation active protons, which is expressed as a Bronsted acidity. This process is affected by the clay hydration status, the polarizing power of the surface bond, and structural cations on mineral colloids (Mortland 1970, 1986). On the other hand, ions such as A1 and Fe, which are exposed at the edge of mineral clay coUoids, induce the formation of Lewis acidity (McBride 1994). [Pg.296]

In our brief introduction to Lewis structures (see Section 2.2), we paid particular attention to valency, the number of bonds an atom could make to other atoms via the sharing of electrons. We must now broaden this idea to consider atoms in a molecule that are no longer neutral, but which carry a formal positive or negative charge. This means we are considering cations and anions, as in ionic bonding. [Pg.46]


See other pages where Lewis structures cations is mentioned: [Pg.19]    [Pg.19]    [Pg.44]    [Pg.188]    [Pg.188]    [Pg.194]    [Pg.268]    [Pg.268]    [Pg.15]    [Pg.191]    [Pg.199]    [Pg.333]    [Pg.653]    [Pg.741]    [Pg.444]    [Pg.234]    [Pg.125]    [Pg.278]    [Pg.461]    [Pg.217]    [Pg.110]    [Pg.50]   
See also in sourсe #XX -- [ Pg.275 ]




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