Some Applications of d- and f-Block Elements

NCERT Reference: Chapter 4 – The d- and f-Block Elements – Section 4.7

Quick Notes

Iron & Steel: Core construction materials; Fe from ore → alloyed with C, Cr, Mn, Ni for strength/corrosion-resistance.
Pigments & Batteries: TiO₂ (white pigment); MnO₂ (dry/alkaline cells); Zn, Ni–Cd/Ni–MH in batteries.
Coinage: Cu/Ni alloys for circulation; Ag, Au for high-value/commemorative issues.
Catalysts: V₂O₅ (SO₂→SO₃), Fe (Haber), Ni (fat hydrogenation), PdCl₂ (Wacker: ethene→ethanal), TiCl₄+AlR₃ (Ziegler–Natta).
Photography: AgBr is light-sensitive (films/papers).
Nuclear: Actinoids (Th, U, Pu) as reactor fuels and in fuel cycles.

Iron & Steel: Iron is produced by reduction of oxides (hematite/magnetite) then alloyed.
- Plain carbon steel: Fe–C (≈0.1–1.5% C) — structural beams, rails.
- Stainless steels: Fe–Cr (≥11% Cr) ± Ni/Mo — corrosion-resistant cutlery, surgical tools.
- High-strength/low-alloy: Fe with Mn, V, Nb — bridges, pipelines.
Galvanisation: Protective Zn coating on steel (sacrificial anode) to prevent rusting.
Special alloys:
- Ni-based superalloys (Ni–Cr–Co–Al–Ti): jet engines, turbines (high T strength/oxidation resistance).
- Cu-alloys: brass (Cu–Zn), bronze (Cu–Sn) — hardware, bearings, sculptures.

Titanium dioxide (TiO₂): Bright, inert white pigment for paints, plastics, paper; UV-blocking in coatings.
Transition-metal colours:
- Cr₂O₃ (green), Fe₂O₃ (red ochre), CoAl₂O₄ (cobalt blue).
- Glass colouring/decolouring: MnO₂ removes green tinge (Fe²⁺); Co compounds give deep blue glass.

Primary: MnO₂ (cathode) in Leclanché/alkaline dry cells; Zn as anode can or powdered anode.
Secondary (rechargeable):
- Lead–acid: Pb/PbO₂ plates (automotive).
- Ni–Cd / Ni–MH: NiOOH cathode; Cd or metal-hydride anode (portable tools).
- Li-ion (extension): transition-metal oxides (e.g., LiCoO₂, LiNiMnCoO₂) — electronics/EVs.

Group 11 metals: Cu, Ag, Au — malleable, corrosion-resistant; traditional coinage and bullion.
Modern coins: durable Cu–Ni alloys or plated steel (e.g., copper-coated steel pennies/low-value coins).

Contact process: V₂O₅ catalyses SO₂ → SO₃ (H₂SO₄ manufacture).
Haber process: Fe (promoted with K₂O, Al₂O₃) converts N₂ + H₂ → NH₃.
Hydrogenation: Ni catalysts harden vegetable oils (fats industry).
Wacker oxidation: PdCl₂/CuCl₂ catalyses ethene → ethanal (acetaldehyde).
Ziegler–Natta polymerisation: TiCl₄ + AlR₃ for polyethylene/polypropylene.
Automotive three-way catalysts: Pt/Rh/Pd reduce NO_x, oxidise CO and unburnt hydrocarbons (emission control).

AgBr (and AgCl): Light-sensitive crystals in photographic films/papers; form latent image that is developed/reduced to Ag(s).
Modern imaging: AgX still used in specialty films, X-ray plates, and some artistic/archival processes.

Cisplatin (Pt): Anticancer drug for testicular, ovarian, bladder cancers.
Gd³⁺ chelates: MRI contrast agents (paramagnetic lanthanoid).
Radioisotopes: Tc-99m (diagnostic imaging), I-131 (thyroid) — note: Tc is d-block.

Permanent magnets: Nd–Fe–B (neodymium is a lanthanoid), Sm–Co — motors, headphones, HDDs.
Optical phosphors: Eu^2+/3+, Tb³⁺ doped materials for LEDs, displays, and fluorescent lamps.
Conductive/transparent oxides: Indium tin oxide (In/Sn) for touchscreens and solar cells (related p-block with d-block dopant chemistry).

Fuels: UO₂, mixed oxides (UO₂–PuO₂, “MOX”), ThO₂ (thorium fuel cycles under research/usage).
Fuel processing: UF₆ in enrichment; Zr-alloy cladding (Zr: corrosion-resistant, low neutron absorption).

Multiple oxidation states → redox flexibility (catalysis, battery electrodes).
Partially filled d/f orbitals → colourful compounds, magnetic behaviour, coordination chemistry.
High melting points & strength → structural alloys, high-temperature applications.