Cassiterite – a Tin and Tantalum Source

Cassiterite

• The name derives from the Greek kassiteros for tin
• Cassiterite has been the chief tin ore throughout ancient history and remains the most important source of tin today
• As often some of the tin atoms are substituted with iron, titanium, zirconium or tantalum, cassiterite, or to be precise, the smelting slag of SnO₂, is in particular, also a source for tantalum
• Belongs to the Rutile mineral group
• Formula: SnO₂
• Space group: P4₂/mnm (No. 136)
• Crystal system: tetragonal
• Crystal class: 4/mmm
• Lattice parameters: a = b = 4.7382(4) Å, c = 3.1871(1), α = β = γ = 90°

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Picture: CarlesMillan – CC BY-SA 3.0

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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).)

• SnO₆ octahedra (slightly distorted) (purple)
• Oxygen (red)

For a 3D interactive version, see also here:

https://skfb.ly/6PzLY

Ref.:

Structural Studies of Rutile-Type Metal Dioxides
A. A. Bolzan, C. Fong, B. J. Kennedy and C. J. Howard
Acta Cryst. B 1997, 53, 373-380
https://doi.org/10.1107/S0108768197001468

 

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