Cerianite-(Ce)

Cerianite-(Ce)
General
Category Oxide
Formula
(repeating unit)		 (Ce,Th)O2
Crystal system Isometric
Crystal class Hexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space group Fm3m
Unit cell a = 5.42 Å; Z = 4
Identification
Color Dark greenish amber-yellow, yellow, buff
Crystal habit octahedra; earthy, massive
Diaphaneity Translucent or transparent
Density 7.20 (synth. material, calc.; approximated)
References [1][2][3]

Cerianite-(Ce) is a relatively rare oxide mineral, belonging to uraninite group with the formula (Ce,Th)O2.[4][3] It is one of a few currently known minerals containing essential tetravalent cerium, the other examples being stetindite and dyrnaesite-(La).[5][6]

Occurrence and association

Cerianite-(Ce) is associated with alkaline rocks, mostly nepheline syenites.[2] It may be found in carbonatites.[3] Cerianite-(Ce) associates with minerals of the apatite group, bastnäsite-group minerals, calcite, feldspar, "fluocerite", "hydromica", ilmenite, nepheline, magnetite, "törnebohmite" and tremolite.[2] It is the most simple cerium mineral known.[3]

Notes on chemistry

Beside thorium cerianite-(Ce) may contain trace niobium, yttrium, lanthanum, ytterbium, zirconium and tantalum.[2]

Crystal structure

For details on crystal structure see cerium(IV) oxide.

References

  1. ↑ Mineralienatlas
  2. 1 2 3 4 "Cerianite-(Ce) - Handbook of Mineralogy" (PDF). Handbookofmineralogy.org. Retrieved 2016-03-04.
  3. 1 2 3 4 "Cerianite-(Ce): Cerianite-(Ce) mineral information and data". Mindat.org. Retrieved 2016-03-04.
  4. ↑ Graham, A.R., 1955. Cerianite CeO2: a new rare-earth oxide mineral. American Mineralogist 40, 560-564
  5. ↑ "Stetindite: Stetindite mineral information and data". Mindat.org. Retrieved 2016-03-04.
  6. ↑ "Dyrnaesite-(La): Dyrnaesite-(La) mineral information and data". Mindat.org. Retrieved 2016-03-04.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.