Tag Archives: Crystal structure

Celestial Celestine

Celestine

  • named from the Latin word caelestis meaning celestial, which in turn is derived from the Latin word caelum meaning sky or heaven because of its often soft blue color
  • pure Celestine is colourless
  • due to lattice defects in Celestine, colour centres are created which give the crystal its characteristic bluish colour
  • these centers are often additionally stabilized by the presence of pottasium ions
  • heating to over 200 °C “cures” these lattice defects and the mineral loses its color
  • radiation with X-rays creates new or more lattice defects and the color returns or can be intensified.
  • Formula: SrSO4
  • Space group: Pnma (No. 62)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters:  a = 8.360 Å, b = 5.352 Å, c = 6.858 Å, αβγ = 90°

Picture: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0


Crystal structure (click on the pictures to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • SO4 tetrahedra (yellow)
  • SrO8 polyhedra (green)
  • Oxygen (red)

For a 3D interactive version, see here:

https://skfb.ly/6zG6R

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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).]

Eucryptite – not an altcoin but millionfold used in the kitchen

β-Eucryptite

  • Named from the Greek for “well” and “concealed”, in reference to its occurrence as intimate intergrowths with the mineral albite
  • It is the main component of the fameous glass-ceramic cooktops for stoves, known in the EU under the trademark Ceran® from Schott AG
  • Formula: LiAlSiO4
  • Space group: P6222 (No. 180)
  • Crystal system: hexagonal
  • Crystal class: 622
  • Lattice parameters: a = b = 10.500 Å, c = 11.194 Å, αβ = 90°, γ = 120°

Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • SiO4 tetrahedra (orange)
  • AlOtetrahedra (light blue)
  • Li (purple/pink)
  • Oxygen (red)

For a 3D interactive version, see here:

https://skfb.ly/6wqY9

Valentinite

Valentinite

  • named in honour of Basilius Valentinus, a writer on alchemy. He is the supposed author of the first book to give a detailed description of antimony and its compounds.
  • Formula: Sb2O3
  • Space group: Pccn (No. 56)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters: a = 4.89960 Å, b = 12.4490 Å, c = 5.41030 Å, α = β = γ = 90°

Picture: Christian Rewitzer | CC BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • corner-connected SbO3 pyramids (purple)
  • Oxygen (red)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/6utNI

Thaumasite – a suprising mineral

Thaumasite

  • first described in 1878 in Sweden and named from the Greek, “thaumazein”, to be surprised, in reference to its unusual composition with carbonate, sulfate and hydroxysilicate anions
  • Formula: Ca3Si(OH)6(CO3)(SO4)
  • Space group: P63 (No. 173)
  • Crystal system: hexagonal
  • Crystal class: 6
  • Lattice parameters: ab = 11.0538 Å, c = 10.4111 Å, α = β = 90°, γ = 120°

Picture: Rob Lavinsky| iRocks.com  | CC BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • CaO8 polyhedra (blue)
  • SiO6 octahedra (orange)
  • SOtetrahedra (yellow)
  • COtrigonalplanar coordination (gray)
  • Oxygen (red)
  • Hydrogen (white)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/6urWZ

Pascoite – a mineral with decavanadate anions

Pascoite

  • Named after its type locality Pasco Province, Peru
  • Formula: Ca3V10O28 · 17 H2O
  • Space group: C2/(No. 12)
  • Crystal system: monoclinic
  • Crystal class: 2/m
  • Lattice parameters: a = 19.586 Å, b = 10.141 Å, c = 10.911 Å, α = γ  = 90°, β = 120.815°

Picture: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

 

  • Clusters of Decavanadate anions [V10O28]6- (orange)
  • CaO7 polyhedra (blue)
  • Oxygen (red)
  • Hydrogen (white)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/696Kr

Osarizawaite – Icosahedra + Octahedra + Tetrahedra

Osarizawaite

  • Named after its type locality Osarizawa mine, Akita Prefecture, Japan
  • Formula: PbCuAl2(SO4)2(OH)6
  • Space group: R-3(No. 166)
  • Crystal system: trigonal
  • Crystal class: -3m
  • Lattice parameters: a = 7.075 Å, b = 7.075 Å, c = 17.248 Å, α = β  = 90°, γ = 120°


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

 

 

  • PbO12 (slightly distorted) icosahedra (gray)
  • SO4 tetrahedra (yellow)
  • Cu/AlO6 octahedra (blue)
  • Oxygen (red)
  • Hydrogen (white)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/6tUsu