Saturday, May 9, 2009

CARBANION AND CATION

Common Anions
Formal Name Formula Alt. Name
Simple Anions
Arsenide As3−
Azide N3−
Bromide Br−
Chloride Cl−
Fluoride F−
Hydride H−
Iodide I−
Nitride N3−
Oxide O2−
Phosphide P3−
Sulfide S2−
Peroxide O22−
Oxoanions
Arsenate AsO43−
Arsenite AsO33−
Borate BO33−
Bromate BrO3−
Hypobromite BrO−
Carbonate CO32−
Hydrogen carbonate HCO3− Bicarbonate
Hydroxide OH−
Chlorate ClO3−
Perchlorate ClO4−
Chlorite ClO2−
Hypochlorite ClO−
Chromate CrO42−
Dichromate Cr2O72−
Iodate IO3−
Nitrate NO3−
Nitrite NO2−
Phosphate PO43−
Hydrogen phosphate HPO42−
Dihydrogen phosphate H2PO4−
Permanganate MnO4−
Phosphite PO33−
Sulfate SO42−
Thiosulfate S2O32−
Hydrogen sulfate HSO4− Bisulfate
Sulfite SO32−
Hydrogen sulfite HSO3− Bisulfite
Anions from Organic Acids
Acetate C2H3O2−
Formate HCO2−
Oxalate C2O42−
Hydrogen oxalate HC2O4− Binoxalate
Other Anions
hydrosulfide HS− Bisulfide
Telluride Te2−
Amide NH2−
Cyanate OCN−
Thiocyanate SCN−
Cyanide CN−



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
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





Stability:
The general stability order of simple alkyl carbocations is: (most stable) 3o > 2o > 1o > methyl (least stable)

This is because alkyl groups are weakly electron donating due to hyperconjugation and inductive effects. Resonance effects can further stabilise carbocations when present.
Structure:


Alkyl carbocations are sp2 hybridised, planar systems at the cationic C centre.
The p-orbital that is not utilised in the hybrids is empty and is often shown bearing the positive charge since it represents the orbital available to accept electrons.


Common Cations
Common Name Formula Historic Name
Simple Cations
Aluminium Al3+
Barium Ba2+
Beryllium Be2+
Cadmium Cd2+
Caesium Cs+
Calcium Ca2+
Chromium(II) Cr2+ Chromous
Chromium(III) Cr3+ Chromic
Chromium(VI) Cr6+ Chromyl
Cobalt(II) Co2+ Cobaltous
Cobalt(III) Co3+ Cobaltic
Copper(I) Cu+ Cuprous
Copper(II) Cu2+ Cupric
Copper(III) Cu3+
Gallium Ga3+
Helium He2+ (Alpha particle)
Hydrogen H+ (Proton)
Iron(II) Fe2+ Ferrous
Iron(III) Fe3+ Ferric
Lead(II) Pb2+ Plumbous
Lead(IV) Pb4+ Plumbic
Lithium Li+
Magnesium Mg2+
Manganese(II) Mn2+ Manganous
Manganese(III) Mn3+ Manganic
Manganese(IV) Mn4+ Manganyl
Manganese(VII) Mn7+
Mercury(II) Hg2+ Mercuric
Nickel(II) Ni2+ Nickelous
Nickel(III) Ni3+ Nickelic
Potassium K+
Silver Ag+
Sodium Na+
Strontium Sr2+
Tin(II) Sn2+ Stannous
Tin(IV) Sn4+ Stannic
Zinc Zn2+
Polyatomic Cations
Ammonium NH4+
Hydronium H3O+
Nitronium NO2+
Uranyl UO22+
Mercury(I) Hg22+ Mercurous

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