TY - JOUR

T1 - Characterization of synthetic and natural gold chalcogenides by electron microprobe analysis, X-ray powder diffraction, and Raman spectroscopic methods

AU - Palyanova, Galina

AU - Beliaeva, Tatiana

AU - Kokh, Konstantin

AU - Seryotkin, Yurii

AU - Moroz, Tatyana

AU - Tolstykh, Nadezda

N1 - Funding Information: The studies were carried out within the framework of the state assignment of the Sobolev Institute of Geology and Mineralogy of Siberian Branch of Russian Academy of Sciences financed by the Ministry of Science and Higher Education of the Russian Federation. This work was carried out with financial support from the Russian Foundation for Basic Research project No 19‐05‐00316a. The authors thank Dr. N. Karmanov, M. Khlestov, and V. Zinina for their help in obtaining the analytical data (the Analytical Center for Multi‐elemental and Isotope Research of the Sobolev Institute of Geology and Mineralogy Russian Academy of Sciences). We are very grateful to the Dr. Philippe Colomban (Associate Editor) and reviewers for their comments and suggestions. Publisher Copyright: © 2022 John Wiley & Sons, Ltd.

PY - 2022/5

Y1 - 2022/5

N2 - Electron microprobe analysis (EMPA), X-ray powder diffraction (XRD), and Raman spectroscopy (RS) were applied to characterize the synthetic gold chalcogenides of the Au–Te–Se–S system and natural analogs from the Gaching deposit (Central Kamchatka, Russia). The EPMA results showed that the synthetic chalcogenides have different Te/Se/S and Au/X (X = Te + Se + S) ratios: AuX2, Au3X10, and AuX. They are similar in composition to natural compounds — calaverite (AuTe2), maletoyvayamite (Au3Te6Se4), and unnamed minerals AuTe0.7Se0.3 and AuSe0.7S0.3. It was established that chalcogenides AuX, Au3X10, and AuX2 have a specific Raman spectra with characteristic peaks. The position of the peaks and the character of the spectra of the synthetic phases and their natural analogs from the Gaching deposit coincide within the limits of accuracy. Different ratios of chalcogenes Te/Se/S in compounds influence the Raman peak positions. The positions of the peaks for natural compounds AuX differ depending on the predominance of Te (AuTe0.7Se0.3) or Se (AuSe0.7S0.3). AuSe synthetic phases consist of a mixture of α- and β-polymorphs. Raman spectroscopy can be used for the identification of natural gold chalcogenides worldwide, which are difficult to diagnose by other methods due to the microscopic grain sizes and close intergrowths with other ore minerals. The similarity of the Raman spectra upon changing the concentrations of Se and S suggests identical structures and possible isomorphism in the composition range of AuTe0.7Se0.3– AuTe0.7Se0.2S0.1, AuTe1.9Se0.1– AuTe1.8Se0.1S0.1, and Au3Te6Se4– Au3Te6S3Se.

AB - Electron microprobe analysis (EMPA), X-ray powder diffraction (XRD), and Raman spectroscopy (RS) were applied to characterize the synthetic gold chalcogenides of the Au–Te–Se–S system and natural analogs from the Gaching deposit (Central Kamchatka, Russia). The EPMA results showed that the synthetic chalcogenides have different Te/Se/S and Au/X (X = Te + Se + S) ratios: AuX2, Au3X10, and AuX. They are similar in composition to natural compounds — calaverite (AuTe2), maletoyvayamite (Au3Te6Se4), and unnamed minerals AuTe0.7Se0.3 and AuSe0.7S0.3. It was established that chalcogenides AuX, Au3X10, and AuX2 have a specific Raman spectra with characteristic peaks. The position of the peaks and the character of the spectra of the synthetic phases and their natural analogs from the Gaching deposit coincide within the limits of accuracy. Different ratios of chalcogenes Te/Se/S in compounds influence the Raman peak positions. The positions of the peaks for natural compounds AuX differ depending on the predominance of Te (AuTe0.7Se0.3) or Se (AuSe0.7S0.3). AuSe synthetic phases consist of a mixture of α- and β-polymorphs. Raman spectroscopy can be used for the identification of natural gold chalcogenides worldwide, which are difficult to diagnose by other methods due to the microscopic grain sizes and close intergrowths with other ore minerals. The similarity of the Raman spectra upon changing the concentrations of Se and S suggests identical structures and possible isomorphism in the composition range of AuTe0.7Se0.3– AuTe0.7Se0.2S0.1, AuTe1.9Se0.1– AuTe1.8Se0.1S0.1, and Au3Te6Se4– Au3Te6S3Se.

KW - Au chalcogenides

KW - Au–Te–Se–S system

KW - EMPA

KW - RS

KW - XRD

UR - http://www.scopus.com/inward/record.url?scp=85126015867&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/ae20fde1-616e-3f77-9456-fa8cafec8a68/

U2 - 10.1002/jrs.6327

DO - 10.1002/jrs.6327

M3 - Article

AN - SCOPUS:85126015867

VL - 53

SP - 1012

EP - 1022

JO - Journal of Raman Spectroscopy

JF - Journal of Raman Spectroscopy

SN - 0377-0486

IS - 5

ER -