The crystal structure of clinoclase, (Cu3AsO4)(OH)3

Ghose, Subrata; Fehlmann, Marc; Sundaralingam, M.

doi:10.1107/s0365110x65001779

Cited by 21 publications

(15 citation statements)

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“…In the crystal structure of clinoclase, the Cu1 and Cu3 sites are in distorted [4+2] octahedral coordination (four short and two long Cu 2+ -O bonds), whereas the Cu2 atom is coordinated by five O atoms to form a CuO 5 square [4+1] pyramid (four short and one elongated Cu 2+ -O bonds; Ghose et al 1965;Eby and Hawthorne 1990). The crystal structure is based upon two-dimensional layers parallel to (100) (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Whereas clinoclase had been known since 1801 (Bournon 1801) and found at more than a hundred localities worldwide, gilmarite was first described by Sarp and Černý (1999) from Roua copper mines, Alpes Maritimes, France. The two minerals are remarkably different in their crystal structures (Ghose et al 1965;Eby and Hawthorne 1990;Sarp and Černý 1999). Due to the higher abundance of clinoclase compared to gilmarite, it has been studied by a number of techniques, including vibrational spectroscopy (Frost et al 2002;Martens et al 2003) and magnetic susceptibility measurements (Lebernegg et al 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Due to the higher abundance of clinoclase compared to gilmarite, it has been studied by a number of techniques, including vibrational spectroscopy (Frost et al 2002;Martens et al 2003) and magnetic susceptibility measurements (Lebernegg et al 2013). Since no H atom positions have been determined in the original structural studies (Ghose et al 1965;Eby and Hawthorne 1990;Sarp and Černý 1999), Lebernegg et al (2013) used density functional theory (DFT) to establish the hydrogen bonding scheme in clinoclase and to investigate the influence of the hydrogen positions on the magnetic coupling. However, questions remain concerning the relative stabilities of well.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen bonding and structural complexity of the Cu3(AsO4)(OH)3 polymorphs (clinoclase, gilmarite): a theoretical study

Krivovichev¹

2017

J. Geosci.

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Density functional theory (DFT) is used to determine positions of H atoms and to investigate hydrogen bonding in the crystal structures of two polymorphs of Cu 3 (AsO 4 )(OH) 3 : clinoclase and gilmarite. Hydrogen bonds in clinoclase involve interactions between hydroxyl groups and O atoms of arsenate tetrahedra, whereas the crystal structure of gilmarite features OH … OH bonding, which is rather uncommon in copper hydroxy-oxysalts. Information-based parameters of structural complexity for clinoclase and gilmarite show that the former is more complex (I G,total = 213.212 bits/cell) than the latter (I G,total = 53.303 bits/cell), which indirectly points out that gilmarite is metastable. This suggestion is supported by the lower density of gilmarite (4.264 g/cm3 ) compared to that of clinoclase (4.397 g/cm 3). The hypothesis of metastable character of gilmarite is in agreement with the Goldsmith's simplexity principle and the Ostwald-Volmer rule.Keywords: hydrogen bonding, clinoclase, gilmarite, density functional theory, structural complexity, metastability Received: 4 January, 2017; accepted: 3 March, 2017; handling editor: J. Plášil clinoclase and gilmarite that would explain the difference in their abundance in nature.Recently, we have developed an approach to quantitative evaluation of structural complexity of minerals by the Shannon information theory that allows determination of this important parameter in terms of information amount per atom and per unit cell (Krivovichev 2012(Krivovichev , 2013. Using statistical arguments, Krivovichev (2016) demonstrated that structural information per atom provides a negative contribution to configurational entropy of crystals and therefore is a physically important parameter.One of the interesting implications of quantitative measures of structural complexity is that it provides the possibility to evaluate Goldsmith's (1953) simplexity principle in numerical terms. This principle states that, under appropriate kinetically favored crystallization regime (such as crystallization from supersaturated solutions or supercooled melts), the crystalline phase that may form in the system is not the most stable one, but very frequently metastable with the structure simpler than that of the stable phase. This principle found many examples in geological systems (Goldsmith 1953;Morse and Casey 1988) and its general validity was confirmed by means of the information-based measures (Krivovichev 2013(Krivovichev , 2015.The note is in order that structural complexity (or simplexity in Goldsmith's terms) is not the only parameter governing formation of metastable phases, but other parameters such as the structure of precursors and prenucleation clusters and influence of other phases during heterogeneous nucleation should be taken into account as

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrogen bonding and structural complexity of the Cu3(AsO4)(OH)3 polymorphs (clinoclase, gilmarite): a theoretical study

Krivovichev¹

2017

J. Geosci.

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“…Each of these minerals occurs in the oxidized zones of copper deposits and olivenite is by far the commonest [3,4]. Cornwallite and clinoclase are rare secondary minerals that crystallise monoclinic, space group P2 1 /a [3,5,6].…”

Section: Introductionmentioning

confidence: 99%

Vibrational spectroscopic study of the arsenate mineral strashimirite Cu8(AsO4)4(OH)4·5H2O—Relationship to other basic copper arsenates

Frost

Sejkora

Čejka

et al. 2009

Vibrational Spectroscopy

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“…6,8 Clinoclase is also monoclinic with point group 2/m and space group P2 1 /a. 6,9,10 Thus the structures of these three phase-related minerals are related and should provide related spectra, which should differ only in terms of the intensity of the bands according to the relative Cu : As : OH mole ratios.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of the phase‐related basic copper arsenate minerals olivenite, cornwallite, cornubite and clinoclase

Frost

Martens

Williams

2002

J Raman Spectroscopy

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The Raman spectra of olivenite, cornwallite and its diamorph cornubite and clinoclase were obtained at 298 and 77 K using a combination of a thermal stage and Raman microscopy. The vibrational spectra of the minerals are different, in line with differences in crystal structure and composition. Some similarity in the Raman spectra of the hydroxyl-stretching region exists, particularly at 298 K. Two hydroxylstretching wavenumbers are observed for each mineral with the bands for clinoclase being well separated. Characteristic differences in the OH deformation regions are observed. Differences are also observed in the arsenate stretching and deformation regions. The OAsO bending modes are identified. The application of Raman microscopy to the study of closely related mineral phases allowed their molecular characterization using their Raman spectrum, thus permitting the rapid identification of phases in complex mixtures of secondary copper arsenates from the oxidized zones of base metal ore bodies.

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The crystal structure of clinoclase, (Cu₃AsO₄)(OH)₃

Cited by 21 publications

References 5 publications

Hydrogen bonding and structural complexity of the Cu3(AsO4)(OH)3 polymorphs (clinoclase, gilmarite): a theoretical study

Hydrogen bonding and structural complexity of the Cu3(AsO4)(OH)3 polymorphs (clinoclase, gilmarite): a theoretical study

Vibrational spectroscopic study of the arsenate mineral strashimirite Cu8(AsO4)4(OH)4·5H2O—Relationship to other basic copper arsenates

Raman spectroscopy of the phase‐related basic copper arsenate minerals olivenite, cornwallite, cornubite and clinoclase

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