Chemistry:Cerianite-(Ce)
| Cerianite-(Ce) | |
|---|---|
.jpg) Yellow powder of the very rare mineral cerianite-(Ce) from Morro do Ferro, Caldas, Minas Gerais, Brazil . | |
| 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) |
| Other characteristics |  Radioactive |
| References | [1][2][3] |
Cerianite-(Ce) is a relatively rare oxide mineral, belonging to uraninite group with the formula (Ce,Th)O2.[3][5] It is one of a few currently known minerals containing essential tetravalent cerium, the other examples being stetindite and dyrnaesite-(La).[6][7]
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. Both ceria and thoria have a fluorite structure.
References
- ↑ Mineralienatlas
- ↑ 2.0 2.1 2.2 2.3 "Cerianite-(Ce) - Handbook of Mineralogy". http://www.handbookofmineralogy.org/pdfs/cerianite-(Ce).pdf. Retrieved 2016-03-04.
- ↑ 3.0 3.1 3.2 3.3 "Cerianite-(Ce): Cerianite-(Ce) mineral information and data". http://www.mindat.org/min-929.html. Retrieved 2016-03-04.
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ Graham, A.R., 1955. Cerianite CeO2: a new rare-earth oxide mineral. American Mineralogist 40, 560-564
- ↑ "Stetindite: Stetindite mineral information and data". http://www.mindat.org/min-38899.html. Retrieved 2016-03-04.
- ↑ "Dyrnaesite-(La): Dyrnaesite-(La) mineral information and data". http://www.mindat.org/min-46510.html. Retrieved 2016-03-04.
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