Keyite – A Complex Copper-Zinc-Cadmium Arsenate

Keyite

• Named after the mineral dealer Charley Key, who discovered some tiny blue crystals of this mineral on a sample of green Adamite
• Formula: Cu₃(Zn,Cd)₄Cd₂(AsO₄)₆· 2 H₂O
• Space group: I2/a (No. 15)
• Crystal system: monoclinic
• Crystal class: 2/m
• Lattice parameters: a = 11.654 Å, b = 12.780 Å, c = 6.268 Å, α = γ = 90°, β = 99.11°

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Picture: CC BY-SA 3.0 | Christian Rewitzer

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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).)

• CuO₄ square-planar units (blue)
• CuO₆ distorted octahedra (blue)
• CdO₆ distorted trigonal prismatic units (pink)
• AsO₄ distorted tetrahedra (green)
• Oxygen (red)
• Oxygen of water molecules (black(

For a 3D interactive version, see here:

https://skfb.ly/67tQD

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