Topic
Austinite
About: Austinite is a research topic. Over the lifetime, 5 publications have been published within this topic receiving 119 citations.
Papers
TL;DR: The application of Raman microscopy to the study of closely related mineral phases of the adelite group has enabled their molecular characterisation as mentioned in this paper, in particular the position of the hydroxyl stretching vibrations and most of the arsenate bands have been identified.
Abstract: The application of Raman microscopy to the study of closely related mineral phases of the adelite group has enabled their molecular characterisation. The adelite group of minerals are orthorhombic arsenates and vanadates of general formula AB2+(XO4)(OH) where X may be As5+ or V5+ and cation A may be Ca or Pb; cation B may be Co or Cu and others. Raman spectroscopy has proven most powerful for the identification of these minerals. In particular the position of the hydroxyl stretching vibrations and most of the arsenate bands have been identified. The two minerals tangeite and calciovolborthite have previously been identified as the same mineral. Raman spectroscopy has proven that the minerals are not identical and have different structures. The application of Raman spectroscopy to the study of these minerals shows that increased distortion of the arsenate anion occur as the cationic substitution from conichalcite to austinite to duftite occurs.
44 citations
TL;DR: The crystal structure of nearly pure austinite, CaZn(AsO 4 )OH, was redetermined (R = 0.014) and the absolute configuration identified as discussed by the authors.
Abstract: Austinite belongs to the adelite mineral group of calcium and lead arsenates, and has the conichalcite/descloizite type of crystal structure. The crystal structure of nearly pure austinite, CaZn(AsO 4 )OH, was redetermined (R = 0.014) and the absolute configuration identified. The space group P2 1 2 1 2 1 and cell parameters a 7.5092(8), b 9.0438(9), c 5.9343(8) Aa match previous data. Zinc octahedra share edges to form chains parallel to c. Arsenic tetrahedra share vertices with the Zn octahedra to generate a compact framework. Calcium square antiprisms share edges to make chains parallel to a that occupy the channels in the zinc-arsenic framework.
23 citations
TL;DR: The first structural report of a natural cobaltaustinite sample (calcium cobalt arsenate hydroxide) based on single-crystal X-ray diffraction data was presented in this paper.
Abstract: This study presents the first structural report of a natural cobaltaustinite sample (calcium cobalt arsenate hydroxide) based on single-crystal X-ray diffraction data. Cobaltaustinite, with the ideal formula CaCo(AsO4)(OH), belongs to the adelite mineral group. The CoO6 octahedra share edges to form chains extending parallel to the c axis, which are cross-linked by Ca2+ ions and by sharing vertices with isolated AsO4 tetrahedra. The Ca2+ ions are situated in square antiprisms formed by eight O atoms. The major structural difference between the five calcium arsenates in the adelite group is shown in the bonding environments around the octahedrally coordinated M2+ cations (M = Cu, Zn, Co, Ni and Mg), with the average M—O distance decreasing from Cu—O in conichalcite, CaCu(AsO4)(OH) to Zn—O in austinite, CaZn(AsO4)(OH), Co—O in cobaltaustinite, Ni—O in nickelaustinite, CaNi(AsO4)(OH), and Mg—O in adelite, CaMg(AsO4)(OH). The donor–acceptor O—H⋯O distance [2.721 (7) A] in cobaltaustinite is similar to those in austinite and nickelaustinite, but different from those in adelite and conichalcite.
9 citations
1 Jan 1997
TL;DR: The crystal structure of nearly pure austinite, CaZn(As04)OH, was redetermined (R = 0.014) and the absolute configuration identified as discussed by the authors, and the space group P212J21 and cell parameters a 7.5092(8), b 9.0438(9), c 5.9343(8) Amatch previous data.
Abstract: Austinite belongs to the adelite mineral group of calcium and lead arsenates, and has the conichalcite/ descloizite type of crystal structure. The crystal structure of nearly pure austinite, CaZn(As04)OH, was redetermined (R = 0.014) and the absolute configuration identified. The space group P212J21 and cell parameters a 7.5092(8), b 9.0438(9), c 5.9343(8) Amatch previous data. Zinc octahedra share edges to form chains parallel to c. Arsenic tetrahedra share vertices with the Zn octahedra to generate a compact framework. Calcium square anti prisms share edges to make chains parallel to a that occupy the channels in the zincarsenic framework.
TL;DR: In this article, the free energy of formation data have been derived for the minerals olivenite, cornubite, clinoclase, adamite, legrandite, euchroite, duftite, conichalcite, austinite, bayldonite, and schultenite at 298.2 K (25 °C).
Abstract: Solution studies have been carried out on natural and synthetic arsenate minerals, which are often found in the oxide zones of base metal orebodies. Solubility products and free energy of formation data have been derived for the minerals olivenite, cornubite, clinoclase, adamite, legrandite, euchroite, duftite, conichalcite, austinite, bayldonite, and schultenite at 298.2 K (25 °C). The data have been used in turn to construct stability field diagrams illustrating the chemical conditions under which the various species may crystallize from aqueous solution. This equilibrium model is then compared with several natural occurrences of the arsenate suites and it is demonstrated that it can be used to explain a number of observed paragenetic sequences. Descriptions of solution conditions which describe the stabilities of the arsenate minerals with respect to more commonly found secondary minerals of Pb(II), Cu(II), and Zn(II) involve more complex calculations and estimates of the likely levels of various dissolved species, but it is shown how these may be taken into account in the development of a more complex equilibrium model.
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2007 | 1 |
| 2003 | 1 |
| 1997 | 2 |
| 1988 | 1 |