Common Alloys
| Alloy | Components | Why It's Harder / Uses |
|---|---|---|
| Bronze | Cu + Sn | Larger Sn atoms distort Cu lattice → harder, high tensile strength. Tools, bells, coinage. |
| Brass | Cu + Zn | Maintains malleability + low friction. Plumbing, musical instruments, antimicrobial door handles. |
| Stainless Steel | Fe + Cr + Ni + C | Chromium forms self-healing oxide layer → corrosion resistance. Surgical instruments, cookware. |
Carbon Nanomaterials
| Material | Structure | Key Properties |
|---|---|---|
| Graphene | Single sp² carbon layer (1 atom thick) | Strongest known material, excellent conductor, transparent, flexible |
| Carbon Nanotubes | Graphene sheet rolled into a cylinder | Extraordinary tensile strength, thermal conductivity, used in microelectronics |
| Fullerene (C₆₀) | Spherical molecule (truncated icosahedron) | Soluble in non-polar solvents, used in drug delivery and lubricants |
Bonding Geometry
sp² vs sp³ Hybridisation in Carbon Allotropes
sp³ (diamond, SiO₂): 4 bonds, tetrahedral, no delocalised electrons → insulator,
extremely hard
sp² (graphite, graphene, CNTs): 3 σ bonds + 1 delocalised π electron → conductor,
planar sheets
AQA GCSE & IB Chemistry
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