Crystal Structural and Raman Vibrational Studies of Bi1-xSb1-xTe2xO4 Solid Solution with 0 ≤ x ≤ 0.1

Loubbidi, L.; Chagraoui, Abdeslam; Yakine, Imane; Orayech, B.; Naji, Mohamed; Igartua, J. M.; Tairi, A.

doi:10.4236/oalib.1101180

Cited by 1 publication

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“…There is a report of the Raman spectrum of synthetic end-member BiSbO 4 by Loubbidi et al (2014). Their spectrum is similar, with features at 790,740,450,425,395,325,250,155 and 140 cm -1 , but the bands have some relative intensity differences and are displaced from those in the kyawthuite spectrum.…”

Section: Raman Spectroscopymentioning

confidence: 96%

Kyawthuite, Bi³⁺Sb⁵⁺O₄, a new gem mineral from Mogok, Burma (Myanmar)

Kampf

Rossman

et al. 2017

Mineral. mag.

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Kyawthuite, Bi3+Sb5+O4, is a new gem mineral found as a waterworn crystal in alluvium at Chaung-gyi-ah-le-ywa in the Chaung-gyi valley, near Mogok, Burma (Myanmar). Its description is based upon a single sample, which was faceted into a 1.61-carat gem.The composition suggests that the mineral formed in a pegmatite. Kyawthuite is monoclinic, space group I2/c, with unit cell dimensions a = 5.4624(4), b = 4.88519(17), c = 11.8520(8) Å, β = 101.195(7)°, V = 310.25(3) Å3and Z = 4. The colour is reddish orange and the streak is white. It is transparent with adamantine lustre. The Mohs hardness is 5½. Kyawthuite is brittle with a conchoidal fracture and three cleavages: {001} perfect, {110} and {110} good. The measured density is 8.256(5) g cm–3and the calculated density is 8.127 g cm–3. The mineral is optically biaxial with 2V = 90(2)°. The predicted indices of refraction are α = 2.194, β = 2.268, γ = 2.350. Pleochroism is imperceptible and the optical orientation is X = b; Y≈ c; Z ≈ a. Electron microprobe analyses, provided the empirical formula (Bi0.823+Sb0.183+)∑1.00(Sb0.995+Ta0.015+)∑1.00O4. The Raman spectrumis similar to that of synthetic Bi3+Sb5+O4. The infrared spectrum shows a trace amount of OH/H2O. The eight strongest powder X-ray diffraction lines are [dobs in Å(I)(hkl)]: 3.266(100)(112), 2.900(66)(112), 2.678(24)(200), 2.437(22)(020,114), 1.8663(21)(024), 1.8026(43)(116,220,204), 1.6264(23)(224,116) and 1.5288(28)(312,132). In the crystal structure of kyawthuite (R1 = 0.0269 for 593 reflections with Fo > 4σF), Sb5+O6 octahedrashare corners to form chequerboard-like sheets parallel to {001}. Atoms of Bi3+, located above and below the open squares in the sheets, form bonds to the O atoms in the sheets, thereby linking adjacent sheets into a framework. The Bi3+ atom is in lopsided 8 coordination,typical of a cation with stereoactive lone electron pairs. Kyawthuite is isostructural with synthetic β-Sb2O4 and clinocervantite (natural β-Sb2O4).

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Section: Raman Spectroscopymentioning

confidence: 96%