Cinnabar (Not delicious)

Cinnabar is an ore containing HgS, or mercury (II) sulfide:

It's a nice red color and pretty easy to get mercury out of - you just cook it, liberating the volatile sulfur and leaving behind mercury metal (volatile too; don't try this at home). It's funny that such a unique metal was isolated so easily.

Back with a real MoTD tomorrow!


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Actually, several of the sulfide ores are this easy to process, Galena (PbS) and Sphalerite (ZnS) can also be simply heated to drive off the sulfer leaving the metal in molten form, of course, early in 1900's and late 1800's a lot of realestate was damaged in southwest missouri by all this sulfer being released into the environment (e.g. Oronogo-Duenweg Mining Belt Superfund Site).

By Ken Clark (not verified) on 27 Jul 2007 #permalink

Cinnabar is in the quartz group, enantiomorphic space groups P3(1)1 and P3(2)21. Grown to a large size hydrothermally. It has immense refractive index (2.9028 and 3.2560 at 620 nm) and optical rotation,

555°/mm at 589.3 nm
320°/mm at 632.8 nm

There are conflicting x-ray crystal structures. Try P Auvrey and F Genet, Bull. Soc. Franc. Mineral. Cristallog. 96 218 (1973).

P3(2)21 (#154)

a = 4.1450
b = 4.1450
c = 9.4960
alpha = 90.0
beta = 90.0
gamma = 120.0
x/a y/b z/c
Hg 0.7198 0.0000 0.6667
S 0.4889 0.0000 0.1667
Extremely parity divergent mass distribution