Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Résumé Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Burns, P. C. Articles by Percival, J. B. Search for Related Content GeoRef GeoRef Citation

ALACRANITE, As₄S₄: A NEW OCCURRENCE, NEW FORMULA, AND DETERMINATION OF THE CRYSTAL STRUCTURE^*

Peter C. Burns^1, and Jeanne B. Percival²

¹ Department of Civil Engineering and Geological Sciences, 156 Fitzpatrick Hall, University of Notre Dame, Notre Dame, Indiana 46556-0767, U.S.A.
² Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada

E-mail address: pburns{at}nd.edu

Between July 20 and August 3, 1998, cruise SO–133 aboard the R/V Sonne completed detailed mapping and sampling of the seafloor around Lihir Island in Papua New Guinea. Sampling of Conical Seamount resulted in the discovery of an unusual occurrence of alacranite and realgar associated with polymetallic vein mineralization consisting of pyrite, sphalerite, galena, minor chalcopyrite and sulfosalts, along with intense clay and silica (amorphous) alteration. Alacranite occurs as subhedral to euhedral tabular orange crystals that are transparent to translucent with a vitreous to resinous luster. Crystals occur both isolated and as groupings within vugs and on matrix, and have a maximum length of 0.1 mm. Single-crystal diffraction data were collected using MoK X-radiation and a CCD-based detector. The structure is monoclinic, space group C2/c, a 9.943(1), b 9.366(1), c 8.908(1) Å, ß 102.007(2)°, and was refined to an agreement index (R1) of 6.6%. The structure determination indicates that the formula of alacranite is As₄S₄, Z = 4, rather than As₈S₉ as reported earlier from a Russian locality. Thus, alacranite is the third polymorph of this composition, after realgar and pararealgar. The structure contains covalently bonded As₄S₄ molecules that are linked by van der Waals forces to form the three-dimensional structure. The structure is identical to that of synthetic –As₄S₄.

Keywords: alacranite, realgar, pararealgar, arsenic sulfide, structure determination, Conical Seamount, Lihir Island, Papua New Guinea.

This article has been cited by other articles:

				P. BALLIRANO and A. MARAS In-situ X-ray transmission powder diffraction study of the kinetics of the light induced alteration of realgar ({alpha}-As4S4) European Journal of Mineralogy, October 1, 2006; 18(5): 589 - 599. [Abstract] [Full Text] [PDF]

				L. Bindi, V. Popova, and P. Bonazzi UZONITE, As4S5, FROM THE TYPE LOCALITY: SINGLE-CRYSTAL X-RAY STUDY AND EFFECTS OF EXPOSURE TO LIGHT Can Mineral, December 1, 2003; 41(6): 1463 - 1468. [Abstract] [Full Text] [PDF]

				P. BONAZZI, L. BINDI, F. OLMI, and S. MENCHETTI How many alacranites do exist? A structural study of non-stoichiometric As8S9-x crystals European Journal of Mineralogy, April 1, 2003; 15(2): 283 - 288. [Abstract] [Full Text] [PDF]