Tongbaite is a rare mineral that has the chemical formula Cr3C2, or chromium carbide.

Tongbaite
General
CategoryCarbide mineral
Formula
(repeating unit)
Cr3C2
IMA symbolTgb[1]
Strunz classification1.BA.15
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPnma
Unit cella = 5.52 Å, b = 11.48 Å
c = 2.82 Å; Z = 4
Identification
ColorPale brownish yellow; pale violet in reflected light
Crystal habitPrismatic crystals, pseudohexagonal
TenacityBrittle
Mohs scale hardness8.5
LusterMetallic
DiaphaneityOpaque
Specific gravity6.64 calculated
References[2][3][4]

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 edit

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b Handbook of Mineralogy
  3. ^ a b c Mindat.org
  4. ^ Webmineral data