Monthly Archives: May 2018

Porous materials, minerals and bees

Thoughtful and very well written. Nice analogy with the bees!

Molecular Dreams

Overwhelmed with the increasing flow of new scientific discoveries and related literature? You’re not alone. We live in the information overload era: too much to read, too little time, and life is short. Probably we’d need more readable, shorter papers too. Why writing a long one? Perhaps, it might connect disciplines which speak different languages but have much in common. Like material science and mineral science.

Let’s start from the first one.

You can make materials for solar cells, optical devices or medical sensors by trapping molecules or nanoparticles inside a “host”. Once there, molecules are no longer free to move, like in a gas or a liquid.  This process, called “confinement”, brings to life new properties, which were not present in the individual molecules and are very useful in technology.  Energy transfer or information storage, for instance, are made possible by the organization of the confined molecules

P1270522 The…

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Ice II (Ice-two)

Ice II (Ice two)

  • can be formed from hexagonal Ice (Ice Ih) at 198 K and 3000 bar or by decompressing Ice-five (Ice V) at 238 K
  • Ice II is likely to be a major rock-forming mineral in the outer Solar System
  • It may form a major proportion of icy moons such as Jupiter’s Ganymede
  • Density: 1.16 g/cm3

Structural features:

  • Ice-two is a proton-ordered form of ice
  • there are two types of 6-membered rings; one is almost flat (Type A) the other one has a more puckered, chair-like conformation (Type B)
  • these two types of rings are strictly alternating stacked along the c axis

  • If you look along the c axis, you will see that the two types of 6-rings are slightly rotated against each other (~ 16 degrees)

  • Space group R-3
  • Lattice parameters:
    • a = b = 12.935 Å, c = 6.233 Å
    • α = β = 90°γ = 120°

  Here, you can download the CIF.

[Atomic structure figures created with VESTA:
K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr.44, 1272-1276 (2011).]