Category Archives: crystal structures

Atacamite and Hibbingite

Atacamite

  • Named after its type locality, the Atacama desert in Chile.
  • Atacamite is isostructural with Hibbingite [Fe2Cl(OH)3], and Kempite [Mn2Cl(OH)3]
  • In 2002 it was found out that the jaws of the marine bloodworm Glycera dibranchiata contain Atacamite.[1]
  • Atacamite is polymorphous with Botallackite and Clinoatacamite (both monoclinic).
  • Formula: Cu2Cl(OH)3
  • Space group: Pnma (No. 62)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters: a = 6.030(2) Å, b =  6.865(2) Å, c = 9.120(2) Å, α = βγ = 90°

Picture: By Stefan Schorn – CC BY-SA 3.0
http://www.mineralienatlas.de/lexikon/index.php/Bildanzeige?pict=1081079762,
https://commons.wikimedia.org/w/index.php?curid=399210


Crystal structure[2] (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).)

  • CuO5Cl distorted octahedra (orange)
  • CuO4Cl2 distorted octahedra (blue)
  • Oxygen (red)
  • Chlorine (green)
  • Hydrogen (white)

For a 3D interactive version, see here:

https://skfb.ly/6QpQY

References:

[1] H.C. Lichtenegger, Th. Schöberl, M.H. Bartl, H. Waite, G.D. Stucky
Science 2002, 298, 389-392.
DOI: 10.1126/science.1075433

[2] J.B. Parise, B.G. Hyde
Acta Cryst. C 1986, 42, 1277-1280.
DOI: 10.1107/S0108270186092570


Hibbingite

  • Named after its type locality, the city of Hibbing, which was built on the rich iron ore of the Mesabi Iron Range. At the edge of the town is the largest open-pit iron mine in the world.
  • Hibbingite is isostructural with Atacamite [Cu2Cl(OH)3] and Kempite [Mn2Cl(OH)3]
  • Formula: Fe2Cl(OH)3
  • Space group: Pnma (No. 62)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters: a = 6.3373(2) Å, b =  6.9892(2) Å, c = 9.3457(3) Å, α = βγ = 90°

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).)

  • FeO5Cl distorted octahedra (green)
  • FeO4Cl2 distorted octahedra (brown)
  • Oxygen (red)
  • Chlorine (green)
  • Hydrogen (white)

For a 3D interactive version, see here:

https://skfb.ly/6QpRS

Reference:

N.V. Zubkova, I.V. Pekov, E.V. Sereda, V.O. Yapaskurt, D.Y. Pushcharovsky
Z. Kristallogr. 2019, 234 (6), 379-382.
DOI: 10.1515/zkri-2018-2124


 

Schoenfliesite

Schoenfliesite

  • Named in 1971 by George T. Faust and Waldemar T. Schaller in honor of Arthur Moritz Schoenflies ( 17 April 1853 – 27 May 1928) Professor of Mathematics, University of Frankfurt. Schoenflies’ researches in group theory and topology resulted in his proof of the 230 space groups.
  • Formula: MgSn(OH)
  • Space group: Pn-3 (No. 201)
  • Crystal system: cubic
  • Crystal class: m-3
  • Lattice parameters: a = b = c = 7.7449(4) Å, α = β = γ = 90°

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).)

  • MgO6 octahedra (orange)
  • SnO6 octahedra (blue-gray)
  • Hydrogen (white)

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

https://skfb.ly/6QpyS

Reference:

Description of Schoenfliesite, MgSn(OH)6, and Roxbyite, Cu1.72S, from a 1375 BC Shipwreck, and Rietveld Neutron-diffraction Refinement of Synthetic Schoenfliesite, Wickmanite, MnSn(OH)6, and Burtite, CaSn(OH)6
L.C. Basciano, R.C. Peterson, P.L. Roeder
The Canadian Mineralogist 1998, 36, 1203-1210.

Spangolite – A Pyroelectric Copper Sulfate Sheet Mineral

Spangolite

  • Named in honour of Norman Spang (1841–1922), a mineral collector from Pennsylvania, USA; for details, see here.
  • Spangolite is pyroelectric
  • Formula: Cu6Al(SO4)(OH)12Cl · 3 H2O
  • Space group: P31(No. 159)
  • Crystal system: trigonal
  • Crystal class: 3m
  • Lattice parameters: a = b = 8.254(4) Å, c = 14.354(8) Å, α = β = 90°, γ = 120°

Picture: Christian Rewitzer, CC BY-SA 3.0
https://commons.wikimedia.org/w/index.php?curid=14865917


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).)

  • CuO6 distorted octahedra (blue)
  • AlO6 octahedra (orange)
  • SOtetrahedra (yellow)
  • Oxygen (red)
  • Chlorine (green)
  • Hydrogen (white)

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

https://skfb.ly/6Q6U7

References:

[1] Spangolite
H. A. Miers
Mineralogical Magazine 1894, 10, 273-277

DOI: 10.1180/minmag.1894.010.48.02

[2] The Crystal Structure of Spangolite, a Complex Copper Sulfate Sheet Mineral
F.C. Hawthorne, M. Kimata, R.K. Eby
American Mineralogist 1993, 78 (5-6), 649-652.

Suzukiite – polymorphic to Bavsiite

Suzukiite

  • Named in honor of Jun Suzuki, a professor of mineralogy and petrology, at the Hokkaido University, Sapporo (Japan).
  • Suzukiite belongs to the inosilicates (chain silicates) and is polymorphic to Bavsiite, which is tetragonal.
  • Formula: BaVSi2O7
  • Space group: Cmcm (No. 63)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters: a = 5.3546(16), b = 15.249(5) Å, c = 7.094(2) Å, α = β = γ = 90°

Picture: D. Nishio-Hamane – CC BY-NC-SA 2.0


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).)

 

  • BaO10 polyhedra (not shown as polyhedra, Ba green)
  • SiO4 tetrahedra (yellow)
  • VO5 square pyramids (purple)
  • Oxygen (red)

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

https://skfb.ly/6Q6GC

Reference:
Crystal Structure of Suzukiite from the Mogurazawa Mine, Gunma Prefecture, Japan,
M. Ito, S. Matsubara, K. Yokoyama, K. Momma, R. Miyawaki, I. Nakai, A. Kato
Journal of Mineralogical and Petrological Sciences 2014, 109, 222-227

DOI: 10.2465/jmps.140520

VMOP-beta

The first densest lattice of chemical supertetrahedra?

In one of the last issues of the Angewandte, Wang and coworkers [1] presented an extremely interesting structure, in which metal-organic polyhedra (MOP) are assembled in different ways. These polyhedra consist of polyoxovanadate metal clusters and bridging dicarboxylate linkers. The authors call them VMOP. The overall shape of the MOP can be described as tetrahedron, or to be precise, as truncated tetrahedron see Fig. 1.

Fig. 1: VMOP, in atomistic representation (left) and simplified as a truncated tetrahedron (right).

In fact, the authors obtained two different phases, which differ in the kind of packing: in the VMOP-alpha isomer (a very low-density phase, which is thermodynamically less stable) each truncated tetrahedron makes perfect contact with four neighbors via the (small) four trigonal faces (the truncated faces), thus leading to a dia-like framework (corner-connected tetrahedra).

However, in VMOP-beta the MOPs are packed in a corner-to-face fashion, i.e. each
truncated tetrahedron has contact with eight neighboring tetrahedra (trigonal-to-hexagonal face-to-face-connection), see Fig. 2.

Fig. 2: The eight direct neighbors of a central truncated tetrahedron (in green) in the packing of VMOP-beta.

This packing mode of regular (non-truncated) tetrahedra is known as the densest lattice packing  (i.e. only translations are allowed) of tetrahedra, which was proven in 1969 by Hoylman [2]. The resulting packing density is 18/49 ≈ 36.73 %. Here, each tetrahedron is in contact with 14 others (4 corners + 4 faces + 6 edges). However, in VMOP-beta the 6 edge-edge connections are a bit further apart.

I think, the structure of VMOP-beta is very remarkable and I am not aware of any analogous chemical structure – do you?

PS: I would like to thank Ahmad Rafsanjani Abbasi (ETH Zürich) for bringing this structure to my attention.

References:

[1] Y. Gong, Y. Zhang, C. Qin, C. Sun, X. Wang, Z. Su, Angew. Chem. Int. Ed. 201958, 780.
https://doi.org/10.1002/anie.201811027

[2] D.J. Hoylman, Bull. Amer. Math. Soc. 1970, 76, 135.
https://doi.org/10.1090/S0002-9904-1970-12400-4

 

Afwillite – a calcium nesosilicate

Afwillite

  • Named after the abbreviated discoverer Alpheus Fuller Williams (1874–1953), CEO of De Beers Consolidated Mines at that time
  • Formula: Ca3(SiO3OH)2 · 2 H2O
  • It belongs to the nesosilicates, i.e. there are only isolated SiO4 tetrahedra
  • Space group: Cc (No. 9)
  • Crystal system: monoclinic
  • Crystal class: m
  • Lattice parameters: a = 16.278 Å, b = 5.6321 Å, c = 13.236, α =  γ = 90°, β = 134.898°

Picture: Matteo Chinellato – http://www.mindat.org/photo-356015.html | 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).)

  • Oxygen (red)
  • Hydrogen (white)
  • SiO4 tetrahedra (yellow)
  • CaO7 polyhedra (light blue)

For a 3D interactive version, see here:

https://skfb.ly/6J7oy

Sartorite

Sartorite

  • Named after Wolfgang Sartorius von Waltershausen (1809 – 1876) Professor of Mineralogy, University of Göttingen, Germany. He was the first who described the mineral.
  • Formula: PbAs2S4
  • Space group: P21/(No. 14)
  • Crystal system: monoclinic
  • Crystal class: 2/m
  • Lattice parameters: a = 19.62 Å, b = 7.89 Å, c = 4.19 Å, α = γ = 90°,  β = 90° (!)

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).)

  • PbS9 polyhedra (gray)
  • AsS3 trigonal pyramids (green)
  • Sulfur (yellow)

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

https://skfb.ly/6IYWO