High temperature and composition induced phase transitions in LiZnV1-xAsxO4 phenacites : Crystal structure and Raman spectroscopy studies

• In this work, using techniques of X-ray diffraction and Raman spectroscopy, we report the composition and high-temperature induced phase transition in the system LiZnV1-xAsxO4 (0 <= x <= 1). Both techniques showed that the increase of arsenic amount induced a structural transition from R-3 LiZnVO4 type to LiZnAsO4 type belonging to R3 space group, the transition occurring between x = 0.7 and x = 0.8. Furthermore, increasing temperature for the compositions (0.8 <= x <= 1) manifests a transition from the LiZnAsO4 structural type with R3 space group to the R-3 LiZnVO4 structural type. For this series, the transition from the space group R3 to the centro-symmetric space group R-3 shows considerable changes in the compositional and temperature dependencies of the bands: spectral positions of all the observed Raman bands exhibit shifts linearly proportional to the temperature increase, with points of shift-rate changes revealing a symmetry change. The Raman-spectra based temperature-composition phase diagram confirms the results obtained using the method of Rietveld refinements, thus showing the R-3 to R3 transition occurring between x = 0.7 and 0.8.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)

Nyckelord

LiZnV1-xAsxO4

Phenacite structure

Phase transition

X-ray diffraction

Rietveld refinements

High temperature Raman spectroscopy

Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics

Geovetenskap med inriktning mot mineralogi, petrologi och tektonik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)