Sillénite

Sillénite or sillenite is a mineral with the chemical formula Bi₁₂SiO₂₀. It is named after the Swedish chemist Lars Gunnar Sillén, who mostly studied bismuth-oxygen compounds. It is found in Australia, Europe, China, Japan, Mexico and Mozambique, typically in association with bismutite.[1][2][3]

Sillénite
Sillénite from Germany
General
Category	Oxide mineral
Formula (repeating unit)	Bi12SiO20
Strunz classification	4.CB.70
Dana classification	16a.03.05.01
Crystal system	Cubic
Crystal class	Tetartoidal (23) H-M symbol: (23)
Space group	I23
Unit cell	a = 10.110 Å, Z = 2
Identification
Color	Olive-green, gray-green, yellow-green, yellow, reddish-brown
Crystal habit	Cubic crystals
Mohs scale hardness	1–2
Luster	Adamantine
Diaphaneity	Translucent
Specific gravity	9.16
Optical properties	Isotropic
Refractive index	>2.5
Birefringence	none
Solubility	Soluble in hydrochloric acid
References	[1][2][3]

Sillenites refer to a class of bismuth compounds with a structure similar to Bi₁₂SiO₂₀, whose parent structure is γ-Bi₂O₃, a meta-stable form of bismuth oxide.[4] The cubic crystal sillenite structure is shared by several synthetic materials including bismuth titanate and bismuth germanate.[5] These compounds have been extensively investigated for their non-linear optical properties.[6][7][8]

Additional stoichiometries, and modified structures, are also found in Bi₂₅GaO₃₉, Bi₂₅FeO₃₉, and Bi₂₅InO₃₉.[9][10] These compounds have gathered recent interest due to their photocatalytic properties.[11]

Recently, sillenites have also gathered interest as heavy metal glass ceramics. They are considered promising materials for laser technology as they combine strong nonlinear properties, relative ease of manufacturing, and low production cost.[12]

References

1. Sillenite. Webmineral
2. Sillenite. Mindat
3. Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1995). "Sillenite" (PDF). Handbook of Mineralogy. II (Silica, Silicates). Chantilly, VA, US: Mineralogical Society of America. ISBN 978-0962209710.
4. Valant, Matjaz, and Danilo Suvorov. "A stoichiometric model for sillenites." Chemistry of materials 14.8 (2002): 3471-3476 | https://pubs.acs.org/doi/abs/10.1021/cm021173l
5. Santos, D. J.; Barbosa, L. B.; Silva, R. S.; MacEdo, Z. S. (2013). "Fabrication and Electrical Characterization of Translucent Bi₁₂TiiO₂₀ Ceramics". Advances in Condensed Matter Physics. 2013: 1–7. doi:10.1155/2013/536754.
6. Marinova, Vera, et al. "Real-time holography in ruthenium-doped bismuth sillenite crystals at 1064 nm." Optics letters 36.11 (2011): 1981-1983. | https://doi.org/10.1364/NP.2010.NTuC12
7. Reyher, H-J., U. Hellwig, and O. Thiemann. "Optically detected magnetic resonance of the bismuth-on-metal-site intrinsic defect in photorefractive sillenite crystals." Physical Review B 47.10 (1993): 5638.
8. Malinovskii, Valerii K., et al. "Photoinduced phenomena in sillenites." Novosibirsk Izdatel Nauka (1990).
9. Scurti, Craig A., et al. "Electron diffraction study of the sillenites Bi12SiO20, Bi25FeO39 and Bi25InO39: Evidence of short-range ordering of oxygen-vacancies in the trivalent sillenites." AIP Advances 4.8 (2014): 087125. | https://doi.org/10.1063/1.4893341
10. Arenas, D. J., et al. "Raman spectroscopy evidence of inhomogeneous disorder in the bismuth-oxygen framework of Bi 25 InO 39 and other sillenites." Physical Review B 86.14 (2012): 144116. | https://doi.org/10.1103/PhysRevB.86.144116
11. Lopes, Armandina ML, João P. Araújo, and Stanislav Ferdov. "Room temperature synthesis of Bi 25 FeO 39 and hydrothermal kinetic relations between sillenite-and distorted perovskite-type bismuth ferrites." Dalton Transactions 43.48 (2014): 18010-18016.DOI:10.1039/C4DT01825G
12. Rejisha, S. R., et al. "Synthesis and characterization of strontium and barium bismuth borate glass-ceramics." Journal of Non-Crystalline Solids 388 (2014): 68-74. || https://doi.org/10.1016/j.jnoncrysol.2014.01.037