Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Electronic counting

Moving now to nitrogen we see that it has four covalent bonds (two single bonds + one double bond) and so its electron count is 5(8) = 4 A neutral nitrogen has five electrons m its valence shell The electron count for nitrogen m nitric acid is one less than that of a neutral nitrogen atom so its formal charge is +1... [Pg.18]

The green oxygen m Figure 1 5 owns three unshared pairs (six electrons) and shares two electrons with nitrogen to give it an electron count of seven This is one more than the number of electrons m the valence shell of an oxygen atom and so its formal charge is —1... [Pg.18]

FIGURE 1 5 Counting electrons in nitnc acid The electron count of each atom is equal to half the number of electrons it shares in covalent bonds plus the number of electrons in its own unshared pairs... [Pg.18]

Valence electrons of neutral atom Electron count Formal charge... [Pg.19]

The electron counts of nitrogen in ammonium ion and boron in borohydride ion are both 4 (half of eight electrons in covalent bonds) Because a neutral nitrogen has five electrons in its valence shell an electron count of 4 gives it a formal charge of +1 A neutral boron has three valence electrons so that an electron count of 4 in borohydride ion corresponds to a formal charge of -1... [Pg.1199]

For main group elements the number of framework electrons contributed is equal to (t + a — 2) where v is the number of valence shell electrons of that element, and x is the number of electrons from ligands, eg, for Ff, x = and for Lewis bases, x = 2. Examples of 2n + 2 electron count boranes and heteroboranes, and the number of framework electrons contributed by their skeletal atoms, ate given in Table 1. [Pg.230]

Some metaHacarboranes present anomahes to the electron-counting formaUsms. Symmetrical sandwich... [Pg.233]

Because the electron-counting paradigm incorporates the 18-electron rule when appHed to transition-metal complexes, exceptions can be expected as found for classical coordination complexes. Relatively minor exceptions are found in (Tj -C H )2Fe2C2BgHg [54854-86-3] (52) and [Ni(B2QH22)2] A [11141-32-5] (53). The former Q,n electrons) is noticeably distorted from an idealized stmcture, and the latter is reminiscent of the and complexes discussed above. An extremely deficient electron count is obtained for complexes such as P7036-06-9] which have essentially undistorted... [Pg.233]

As the C B series of tetracarbaboranes is classified in the electron-counting formaUsm as nido, these molecules are expected to have open stmctures even though extra hydrogens are absent. Spectroscopic studies (130) have confirmed this expectation for 2,3,4,5-C4B2H3 [28323-17-3]. One isomer of (CH3)4C4BgHg has the open nonicosahedral stmcture shown in Figure 11 and another isomer, the 1,2,3,8-tetramethyl compound [54387-54-1], is apparently even more open (131). Other tetracarbaboranes include isomers of nido-Q]. and (132). [Pg.241]

The closo, nido, arachno classification is given on the basis of framework electron count and not stmcture. [Pg.243]

The first closo metaHaborane complexes prepared (159) were the nickelaboranes [< /(9j 0-( q -C H )Ni(B22H22)] and closo-l]l- r]-Q ]) -l]l-53i] pri Q [55266-88-1] (Fig. 13). These species are equivalent to closo-C ]]ri ][ i closo-Q, p5 2 by tbe electron-counting formaUsm. The mixed bimetallic anion [ /(9j (9-(Tj -C H )2CoNi(B2QH2Q)] and other related species were reported later (160). These metallaboranes display remarkable hydrolytic, oxidative, and thermal stabiUty. [Pg.243]

Characterization of these clusters indicate an unusual 2n framework electron count having geometries reminiscent of stricdy metallic clusters (11,164). [Pg.244]

For tetranuclear cluster complexes, three stmcture types are observed tetrahedral open tetrahedral (butterfly) or square planar, for typical total valence electron counts of 60, 62, and 64, respectively. The earliest tetracarbonyl cluster complexes known were Co4(CO)22, and the rhodium and iridium analogues. The... [Pg.64]

The emitted P particles excite the organic molecules which, in returning to normal energy levels, emit light pulses that are detected by a photomultiplier tube, amplified, and electronically counted. Liquid scintillation counting is by far the most widely used technique in tritium tracer studies and has superseded most other analytical techniques for general use (70). [Pg.15]


See other pages where Electronic counting is mentioned: [Pg.257]    [Pg.280]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.19]    [Pg.48]    [Pg.459]    [Pg.329]    [Pg.228]    [Pg.229]    [Pg.229]    [Pg.230]    [Pg.230]    [Pg.231]    [Pg.233]    [Pg.233]    [Pg.234]    [Pg.234]    [Pg.244]    [Pg.265]    [Pg.4]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.19]   
See also in sourсe #XX -- [ Pg.56 , Pg.77 , Pg.78 , Pg.93 ]




SEARCH



18-electron count, alkyne complexes

Ambiguity in the electron count for carbene complexes

An orbital explanation of electron-counting rules

Aromatic compounds electron count rules

Atoms electron counting

Bonding and Electron Counting

Bonding electron counting rules

Bridging electron counting

Bridging ligands electron counting

Cage structures electron counting

Carbon electron counting

Catalytic reactions electron counting

Cation electron counting

Cluster compounds Electron counting

Cluster valence electron counts

Clusters, metal electron counting

Coordination Geometries and Electron Counts

Counting Electrons Coulometry and Faradays Law of Electrolysis

Counting complexes Electron affinities

Counting electrons in metal clusters

Counting electrons, 18-electron rule

Covalent bonds electron counting

D electron count

D-Electrons counting

Digital Electronics for Ion Counting Detectors

Donor pair electron counting

Donor pair electron counting formalism

Electron Counting and Oxidation State

Electron Counting in Reactions

Electron count cluster-fusion rule

Electron count hypercloso

Electron count in a complex the covalent model

Electron count rationalizations

Electron count rules

Electron count, polyhedral

Electron counting

Electron counting Zintl ions, 401

Electron counting applications

Electron counting basic principles

Electron counting borane cluster compounds, 364

Electron counting carbaboranes, 370

Electron counting carborane

Electron counting cluster

Electron counting cluster hydrides

Electron counting common ligands

Electron counting complexes

Electron counting compounds

Electron counting formalism

Electron counting in transition metal complexe

Electron counting isoelectronic compound

Electron counting main-group cluster fragments

Electron counting metal carbonyls

Electron counting methods

Electron counting platinum clusters

Electron counting rule cluster valence electrons

Electron counting structure correlations

Electron counting, extended

Electron counting, in transition metal

Electron counting, in transition metal complexes

Electron counts

Electron counts

Electron counts, of ligand contributions

Electron multiplier pulse counting

Electron-counting and isolobal relationships

Electron-counting procedure

Electron-counting rules

Electron-counting rules transition element compounds

Electron-counting scheme for macropolyhedral boranes mno rule

Electron-counting schemes

Electronic cell counting

Electronic sizing and counting of particles

Electronics, photon-counting

Fermi level and electron counting

Fractional electron count

Halogens electron counting

Heteroatoms electron counting

Higher Electron Counts

Huckel electron counting rule

Hydrogen electron counting

Isoelectronic cluster electron counting

Isoelectronic cluster skeletal electron count

LX “half-arrow” electron-counting

Ligand contributions, electron counts

Ligand synthesis electron counting

Ligands and electron counting

Localized electron count

Metal Bonding and Electron Counting in Polynuclear Complexes

Metal clusters electron counting procedures

Metal-ligand complexes electron counting

Metalloboranes electron counting

Mingos cluster valence electron count

Mingos cluster valence electron count schemes

Molecular orbital electron counting rule

Nitrogen electron counting

Oxidation State and Electron Count

Oxygen electron counting

Palladium complexes electron count

Palladium complexes electron counting

Particle counting apparatus, electronic

Pericyclic reactions electron counting

Phosphine ligands electron count

Remarks on the chemical bond factor and valence-electron counting rules

Rules for Cluster Structure-Electron Counting Correlations

SQUARE PLANAR, TETRAHEDRAL ML4 COMPLEXES AND ELECTRON COUNTING

Skeletal electron counting formulae

Skeletal electron counting rules

Square antiprismatic geometry electron counting

Structural Types, Electron Counts, and Isolobal Units

Summary of electron counting

The Wade-Mingos electron-counting rule

Topological electron-counting model

Total electron count

Total electron count, calculation

Total valence electron counting schemes

Total valence electron counts in d-block organometallic clusters

Transition metal clusters skeletal electron counting

Transition metal complexes electron counting

Transition metal ligand contributions, electron counts

Typical Ligands Total Electron Count

Valence electron count

Valence electron counts listed for various cluster frameworks

Valence electron counts, iron clusters

Valence electrons counting

Valence-electron counting rules,

Wade electron counting rules borane-like cluster nomenclature

© 2024 chempedia.info