Tongbaite
(repeating unit)Cr3C2 IMA symbol Tgb[1] Strunz classification 1.BA.15 Crystal system Orthorhombic Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) Space group Pnma Unit cell a = 5.52 Å, b = 11.48 Å
c = 2.82 Å; Z = 4 Identification Color Pale brownish yellow; pale violet in reflected light Crystal habit Prismatic crystals, pseudohexagonal Tenacity Brittle Mohs scale hardness 8.5 Luster Metallic Diaphaneity Opaque Specific gravity 6.64 calculated References [2][3][4]
H-M symbol: (2/m 2/m 2/m)
c = 2.82 Å; Z = 4
Tongbaite is a rare mineral that has the chemical formula Cr3C2, or chromium carbide.
It was first described in 1983 for an occurrence in Liu village, Tongbai County (桐柏县), Henan Province, China and named for the locality.[3] It occurs in an ultramafic rock deposit.[2] It has also been found in the Tibet Autonomous Region and the Isovsky District, in the Urals of Russia.[3]
References
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