Preparation of non-stoichiometric Arsenic sulphide crystals As2S2.15, and measurement of their electrical conductivity

Kothiyal, G.P.; Ghosh, Biplab

doi:10.1016/0022-0248(76)90006-3

Cited by 11 publications

(5 citation statements)

References 16 publications

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“…Empty symbols refer to data from literature. Down triangle: synthetic -As 4 S 4 (Porter & Sheldrick, 1972); square: synthetic As 2 S 2.15 (Kothiyal & Ghosh, 1976); circle: alacranite from Kamchatka (Popova et al, 1986). …”

Section: Resultsmentioning

confidence: 99%

“…Empty symbols refer to data from literature. Down triangle: syntheticAs 4 S 4 (Porter & Sheldrick, 1972); square: synthetic As 2 S 2.15 (Kothiyal & Ghosh, 1976); circle: alacranite from Kamchatka (Popova et al, 1986); up triangle: synthetic As 4 S 5 (Whitfield, 1973). named. On the other hand, the name alacranite was approved for a mineral with the chemical formula As 8 S 9 (Popova et al, 1986).…”

Section: Discussionmentioning

confidence: 99%

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How many alacranites do exist? A structural study of non-stoichiometric As8S9-x crystals

Bonazzi¹,

Bindi²,

Olmi³

et al. 2003

ejm

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Crystals of arsenic sulphide (reported as alacranite), coming from the burning dump of KateÏ rina Mine (Czech Republic), have been investigated by single crystal X-ray diffraction and chemical microanalysis.Both analytical data and unit-cell parameters strongly suggest the existence of a continuous series between the high-temperature polymorph ( -As 4 S 4 ) and the mineral alacranite (As 8 S 9 ). As the S content increases in the series, the unit-cell volume increases accordingly. The structural model has been obtained for two crystals, exhibiting different unit-cell volumes (ALA15: a = 9.940(2), b = 9.398(2), c = 9.033(2), =102.12(2), V = 825.0(3), R obs = 6.12 %; ALA2: a = 9.936(2), b = 9.458(2), c = 9.106(2), = 101.90(2), V = 837.3(3), R obs = 6.41 %). We found that the non-stoichiometric compounds crystallize as a disordered mixture of two kinds of cage-like molecules, packed together as in the -As 4 S 4 phase. The first one is identical to the As 4 S 4 molecule found in the structures of both realgar ( -As 4 S 4 ) and -As 4 S 4 . The second molecule is chemically and structurally identical to that found in the As 4 S 5 compound. The simultaneous presence of As 4 S 4 (C2/c) and As 8 S 9 (P2/c) microdomains could be a reason for the observed gradual change of the translation symmetry from the -phase to alacranite s.s..

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

How many alacranites do exist? A structural study of non-stoichiometric As8S9-x crystals

Bonazzi¹,

Bindi²,

Olmi³

et al. 2003

ejm

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“…Variation of the unit-cell parameters as a function of the unitcell volume along the join b-As 4 S 4 -alacranite. Symbols: open circle ¼ b-As 4 S 4 phase (B2 crystal; Bonazzi et al, 1996); open square ¼ b-As 4 S 4 phase (Porter and Sheldrick, 1972); filled circles, open star, and crosses ¼ non-stoichiometric As 4 S 4 þ x from Katerina Mine, Czech Republic (Bonazzi et al, 2003a), Lazaresti, Romania (authors' unpublished data) and Khaidarkan, Kyrgyzstan (authors' unpublished data), respectively; open rightward triangle ¼ synthetic As 4 S 4.30 (Kothiyal and Ghosh, 1976); downward triangle and filled star ¼ alacranite from the type locality (Bonazzi et al, 2003b;Popova et al, 1986).…”

Section: ) -Non-stoichiometric Sulfidesmentioning

confidence: 98%

A crystallographic review of arsenic sulfides: effects of chemical variations and changes induced by exposure to light

Bonazzi¹,

Bindi²

2008

Zeitschrift Für Kristallographie - Crystalline Materials

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Crystal data for natural and synthetic arsenic sulfides are reported and discussed. Most of them [a-and b-dimorphite, realgar, b-As 4 S 4 phase, pararealgar, Kutoglu's As 4 S 4 (II) phase, alacranite, uzonite, orthorhombic As 4 S 5 phase] have a crystal structure consisting of a packing of cage-like, covalently bonded As 4 S n (n ¼ 3, 4 and 5) molecules held together by weak interactions of van der Waals character. Their structures are compared in terms of molecular packing and molecular parameters. The layered structural arrangement of orpiment, As 2 S 3 , is described and the effects of the incorporation of Se replacing for S is discussed. The structures of wakabayashilite and getchellite, which contain mixed (As, Sb) coordination polyhedra, are also described to outline the geometric effects of the Sb ! As substitution. The results of recent studies dealing with the effects of the exposure of realgar or other arsenic sulfides to visible light are reported and discussed. Their interest in the study of arsenical pigments and their preservation in artwork is outlined with some examples of application.

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“…FIGURE 4. Unit-cell volume vs. the S content (atoms per As 4 unit); empty circles refer to As 8 S 9-x compounds (Kothiyal and Ghosh 1976;Bonazzi et al 2003); filled circles refer to alacranite from Kamchatka (Popova et al 1986; this study); diamonds: synthetic b-As 4 S 4 (Porter and Sheldrick 1972;Bonazzi et al 1996); square: synthetic As 4 S 5 (Whitfield 1973a); empty up-triangle and star refer to a-dimorphite (Whitfield 1970) and b-dimorphite (Whitfield 1973b), respectively; down-triangle refers to duranusite (Márquez-Zavalía et al 1999). Data fit the regression line: y = 407.6 + 99.6x; r = 0.992.…”

Section: Crystal Chemical Remarksmentioning

confidence: 99%

Alacranite, As8S9: structural study of the holotype and re-assignment of the original chemical formula

Bonazzi

Bindi

Попова

et al. 2003

American Mineralogist

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Alacranite from the type locality (Uzon caldera, Kamchatka, Russian Federation) was submitted for structural analysis. A single crystal was selected and the following lattice parameters were determined: a = 9.942(4), b = 9.601(2), c = 9.178(3) Å, b = 101.94(3)∞, V = 857.1 (5) Å 3 . The crystal structure was solved in the P2/c space group using direct methods and refined to R = 6.79% for 472 observed reflections. The structure of alacranite consists of an ordered sequence of As 4 S 4 and As 4 S 5 cage-like molecules, with a molecular packing closely resembling that found in the b-As 4 S 4 phase. Both As-As and As-S intramolecular distances are in the range usually observed for covalent bonds. The structural model confirms the chemical formula As 8 S 9 for alacranite, and accounts for differences in the unit-cell parameters of alacranite compared to those of the natural analogue of b-As 4 S 4 . This latter mineral, therefore, should receive a new name.

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Preparation of non-stoichiometric Arsenic sulphide crystals As2S2.15, and measurement of their electrical conductivity

Cited by 11 publications

References 16 publications

How many alacranites do exist? A structural study of non-stoichiometric As8S9-x crystals

How many alacranites do exist? A structural study of non-stoichiometric As8S9-x crystals

A crystallographic review of arsenic sulfides: effects of chemical variations and changes induced by exposure to light

Alacranite, As8S9: structural study of the holotype and re-assignment of the original chemical formula

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