Question

explain oxidation state of lanthnoid actinoid​

Answer 1

Answer:

Lanthanides exhibit the oxidation state of +3. Some of them also exhibit the oxidation state of +2 and +4. It is observed that in lanthanide series, there is a progressive decrease in the atomic and ionic radii with increasing atomic number .

Answer 2

Answer:

Explanation:

Lanthanides & Actinides

Actinide Oxidation States

Survey of Actinide Oxidation States

The known oxidation states of the actinides are indicated and surveyed:

**importance: > >

7

6

5

4

3

2

Ac

Th

Pa

U

Np

Pu

Am

Cm

Bk

Cf

Es

Fm

Md

No

Lr

+2

Unusual oxidation state

Common only for the heaviest elements

No2+ & Md2+ are more stable than Eu2+

Actinide An2+ ions have similar properties to Lanthanide Ln2+ and to Ba2+ ions

rationalization of stabilities: Open University Course Book p. 54-56

+3

The most common oxidation state

The most stable oxidation state for all trans-Americium elements (except No?)

Of marginal stability for early actinides Th, Pa, U (But: Group oxidation state for Ac)

General properties resemble Ln3+ and are size-dependent

stability constants of complex formation are similar for same size An3+ & Ln3+

isomorphism is common

later An3+ & Ln3+ must be separated by ion-exchange/solvent extraction

Binary Halides, MX3 easily prepared, & easily hydrolysed to MOX

Binary Oxides, M2O3 known for Ac, Th and trans-Am elements

+4

Principal oxidation state for Th

Th4+ chemistry shows resemblance to Zr4+ / Hf4+ - is it a transition metal?

Very important, stable state for Pa, U, Pu

Am, Cm, Bk & Cf are increasingly easily reduced - only stable in certain complexes

e.g. Bk4+ is more oxidizing than Ce4+

MO2 known from Th to Cf (fluorite structure)

MF4 are isostructural with lanthanide tetrafluorides

MCl4 only known for Th, Pa, U & Np

Hydrolysis / Complexation / Disproportionation are all important in (aq)

+5

Principal state for Pa

Pa5+ chemistry resembles that of Nb5+ / Ta5+ - is it a transition metal?

For U, Np, Pu and Am the AnO2+ ion is known (i.e. quite unlike Nb/Ta)

Comparatively few other AnV species are known

e.g. fluorides, PaF5, NbF5, UF5; fluoro-anions, AnF6-, AnF72-, AnF83-

e.g. oxochlorides, PaOCl3, UOCl3; uranates, NaUO3

+6

AnO22+ ions are important for U, Np, Pu, Am

UO22+ is the most stable

Few other compoundse.g. AnF6 (An = U, Np, Pu), UCl6, UOF4etc... , U(OR)6

+7

Only the marginally stable oxo-anions of Np and Pu, e.g. AnO53-

--Info & DownloadsBibliography [textbook & online resources]

Source: Dr. S.J. Heyes; University of Oxford