Raman spectroscopy of the basic copper arsenate mineral: euchroite

Abstract

Raman spectroscopy complemented with infrared spectroscopy was used to study the molecular structure of the mineral euchroite, a mineral involved in a complex set of equilibria between the copper hydroxy arsenates: euchroite Cu 2 (AsO 4 )(OH)·3H 2 O → olivenite Cu 2 (AsO 4 )(OH) → strashimirite Cu 8 (AsO 4 ) 4 (OH) 4 ·5H 2 O → arhbarite Cu 2 Mg(AsO 4 )(OH) 3 . The Raman bands observed at 848 and 768 cm −1 are assigned to the ν 1 and ν 3 (AsO 4 ) 3− stretching vibrations. Two Raman bands at 358 and 385 cm −1 are attributed to the ν 2 (AsO 4 ) 3− bending mode and two Raman bands at 441 and 474 cm −1 to the ν 4 AsO 4 3− bending modes. Two sharp Raman bands are observed at 3470 and 3537 cm −1 and are attributed to the stretching vibrations of hydroxyl units. A comparison of the Raman spectrum of euchroite is made with the other copper hydroxy arsenate minerals including strashimirite, olivenite, cornubite, and cornwallite.

Mineralogy and origin of supergene mineralization at the Farbište ore occurrence near Poniky, central Slovakia

“…Its refined unit-cell parameters (Tab. 12) are in good agreement with the data given by Eby and Hawthorne (1989) same as Frost et al (2010). Typical for euchroite in BSE images is parquet-like pattern of fracturing of crystals (Fig.…”

“…13). Characteristic of the first type (leek-to emerald-green crystals with euhedral olivenite inclusions) are P contents in the range 0.06-0.07 apfu; its empirical formula on the basis of (As + P) = 1 apfu is Cu same mineral from Svätodušná deposit, Lubietová, Slovak Republic (Anthony et al 2000;Frost et al 2010). Interesting is the F content of 0.02-0.03 apfu in all types of the studied samples, as such elevated fluorine concentrations were not reported as yet for this species.…”

Raman spectroscopy of hydrogen‐arsenate group (AsO3OH) in solid‐state compounds: cobalt mineral phase burgessite Co2(H2O)4[AsO3OH]2·H2O

“…The observed infrared bands are compara- ble with those inferred from RRUFF database and the original description of burgessite by Sejkora et al, [5] and other hydrogen-arsenate minerals, e.g. geminite, [1] haidingerite and brassite, [2] pharmacolite [3] and dussertite. [4] The Raman bands of synthetic erythrite observed at 1571, 1621, 1641 and 1682 cm −1 [9] and infrared bands of erythrite at 1579, 1649 and 1684 cm −1 (inferred from RRUFF R050073) are assigned to the δ (ν 2 ) bending vibrations of structurally non-equivalent water molecules.…”

The mineral tooeleite Fe6(AsO3)4SO4(OH)4⋅4H2O – An infrared and Raman spectroscopic study-environmental implications for arsenic remediation

“…The crystal data was corrected from orthorhombic to 11 monoclinic structure, space group C2/m [3], and the cell dimensions are a = 8.9575 Ǻ, 12 b = 6.4238 Ǻ, c = 9.7912Ǻ, β = 96.032°, unit-cell volume (V) = 560.27 Ǻ 3 . 13 14 There have been some spectroscopic studies using both infrared and Raman 15 spectroscopy of aqueous arsenite species and arsenite containing minerals [6][7][8][9]. The 16 interest in tooeleite research mainly stems from its controlling of arsenic transport in 17 acid mine drainage and its potential significance of fixing arsenic (III) in 18 hydrometallurgical processing [1,2,4].…”

“…However, no spectroscopic studies of this 19 mineral have been undertaken. The aim of this paper is to report the infrared and 20 Raman spectra of tooeleite and to relate the spectra to the structure of the mineral. …”