UPSC Combined Geo-Scientist, Mains · 2024 · Mains Paper I
Q6(c)(ii). Non-stoichiometry of f-block oxides
Question
Discuss the following observation: (ii) Many actinoid oxides are non-stoichiometric but few lanthanoid oxides are.
Answer in brief
Accessible actinoid oxidation states allow oxygen excess or deficiency to be charge-compensated; most lanthanoids strongly favour +3.
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Coversnon-stoichiometric oxidesactinide oxidesUO2+xlanthanide oxidation statesvariable valence
All parts of Question 6
- 6(a) Thermal decomposition of calcium oxalate15 marks
- 6(b) Organic precipitating reagents5 marks
- 6(c)(i) Lanthanoid–EDTA formation enthalpy5 marks
- 6(c)(ii) Non-stoichiometry of f-block oxides5 marks