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Guildite, a layer structure with a ferric hydroxy-sulphate chain and its optical absorption spectra

Wan, Che'ng and Ghose, Subrata and Rossman, George R. (1978) Guildite, a layer structure with a ferric hydroxy-sulphate chain and its optical absorption spectra. American Mineralogist, 63 (5-6). pp. 478-483. ISSN 0003-004X. https://resolver.caltech.edu/CaltechAUTHORS:20130514-072131969

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Abstract

Guildite, Cu^(2+)Fe^(3+)(SO_4)_2(0H)·4H_2O, from the United Verde Mine, Jerome, Arizona, is monoclinic, space group P2_1/m, with cell dimensions ɑ = 9.786(2), b = 7.134(1), c = 7.263(1)A,β = 105.28(1)°, Z = 2. The crystal structure has been determined by Patterson and Fourier syntheses and refined by the method of least squares to an R factor of 0.056 for 942 reflections, measured on an automatic single-crystal diffractometer. The crystal structure contains an octahedral-tetrahedral chain, which consists of zig-zag chains of [FeO_5(OH)] octahedra sharing the (OH) corner; two pairs of octahedral corners on either side of this chain are shared by S(1)O_4 and S(2)O_4 tetrahedra. These chains are crosslinked through corner-sharing trans-[CuO_2(H_O2)_4 ] octahedra into corrugated sheets parallel to the (001) plane. Adjacent sheets are hydrogen-bonded through water molecules. The average Fe^(3+)-O and S-O bond lengths are 2.005 and 1.472A respectively. Cu^(2+) shows the usual Jahn-Teller distortion with four short Cu-O(W) bonds (av. 1.985A) and two long Cu-0 bonds (av. 2.264A). The pleochroism in guildite is similar to that of other materials containing hydroxobridged Fe^(3+) chains. Intense color and the highest refractive index occur when the vibration direction of the incident light is along the chain direction. An intense absorption band at 430 nm and a band at 874 nm are due to Fe^(3+), whereas broad absorption bands at 1285 nm and 780 nm have been assigned to Cu^(2+). Additional bands, including a sharp band at 1953 nm, are due to (OH) ions and water molecules.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://www.minsocam.org/msa/collectors_corner/amtoc/toc1978.htmPublisherUNSPECIFIED
ORCID:
AuthorORCID
Rossman, George R.0000-0002-4571-6884
Additional Information:© 1978 Mineralogical Society of America. Manuscript received, July 15, 1977; accepted for publication, December 5, 1977. We are indebted to John S. White, Jr., Smithsonian Institution, Washington, D.C., for providing the guildite crystal, and to Roger Baker, University of Washington, for the collection of the intensity data. This research has been supported in part by the NSF grants EAR 76-13373 (S .G.) and EAR 76-02014 (G.R.R.).
Funders:
Funding AgencyGrant Number
NSFEAR 76-13373
NSFEAR 76-02014
Issue or Number:5-6
Record Number:CaltechAUTHORS:20130514-072131969
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130514-072131969
Official Citation:Guildite, a layer structure with a new type of ferric hydroxy-sulphate chain and its optical absorption spectra Che'ng Wan, Subrata Ghose and George R. Rossman 478-483, 1978
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:38475
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:14 May 2013 15:09
Last Modified:26 Nov 2019 11:15

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