Plastic Ice (The Fourth Form of Water)
Why in news?
Plastic Ice (Plastic Ice VII) is a newly confirmed, fourth form of water ice distinct from ordinary ice, liquid, and vapor. It occurs under extreme pressure and temperature conditions.
Key Characteristics:
- Molecular Behavior: While it maintains a rigid crystalline (cubic) structure like a solid, the water molecules inside can rotate freely within this lattice, a feature similar to molecules in a liquid.
- This molecular rotation inside a solid lattice is why it's called "plastic" ice—"plastic" refers to its ability to deform under pressure while retaining solidity, showing plasticity unlike conventional ice.
- The structure allows it to behave as a hybrid between solid and liquid phases, a unique state unseen in normal ice forms.
Discovery:
- First predicted theoretically in 2008, Plastic Ice VII was confirmed experimentally around 2025 by an international team led by physicist Livia Bove at Sorbonne University, France.
- Scientists used quasi-elastic neutron scattering (QENS) combined with diamond-anvil cells to create and study tiny samples under extreme conditions, directly observing the rotational motion of molecules at the atomic scale while the lattice remained intact.
Applications & Significance:
- Planetary Science: Explains water’s behavior inside icy moons (Ganymede, Callisto, Titan) and exoplanets.
- Extreme Environment Research: Helps in understanding high-pressure physics and material science.
- Space Exploration: Improves knowledge of ice phases in extreme planetary conditions, aiding in future astrobiology studies.
- Hydrogen Storage & Energy Research: May have potential technological applications in material sciences.
Summary Table of Major Properties
| Property |
Plastic Ice VII |
Ordinary Ice |
| Molecular arrangement |
Rigid cubic crystalline lattice |
Hexagonal or other crystal forms |
| Molecular motion |
Molecules rotate freely within lattice |
Fixed, no free rotation |
| Formation conditions |
Pressure >3 GPa, Temperature >450 K |
Near atmospheric pressure, below 0°C |
| Physical behavior |
Solid with plasticity (deformable) |
Brittle solid |
| Planetary occurrence |
Interiors of icy moons and exoplanets |
Earth's surface, common ice |
Plastic Ice VII adds a fundamental new phase to H2O, expanding our comprehension of water's versatility in nature, especially beyond Earth
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