Skip to main content Accessibility help
×
Home
Hostname: page-component-564cf476b6-2fphr Total loading time: 0.225 Render date: 2021-06-19T23:04:36.388Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": true, "newCiteModal": false, "newCitedByModal": true, "newEcommerce": true }

Bettertonite, [Al6(AsO4)3(OH)9(H2O)5]·11H2O, a new mineral from the Penberthy Croft mine, St. Hilary, Cornwall, UK, with a structure based on polyoxometalate clusters

Published online by Cambridge University Press:  02 January 2018

I.E. Grey
Affiliation:
CSIRO Mineral Resources, Private Bag 10, Clayton South, Victoria 3169, Australia
A.R. Kampf
Affiliation:
Mineral Sciences Dept., Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, U.S.A.
J.R. Price
Affiliation:
Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
C.M. Macrae
Affiliation:
CSIRO Mineral Resources, Private Bag 10, Clayton South, Victoria 3169, Australia
Corresponding
E-mail address:

Abstract

Bettertonite, ideally [Al6(AsO4)3(OH)9(H2O)5]·11H2O, is a new mineral from the Penberthy Croft mine, St. Hilary, Cornwall, England, UK. It occurs as tufts of white, ultrathin (sub-micrometre) rectangular laths, with lateral dimensions generally <20 μm. The laths are flattened on {010} and exhibit the forms {010}, {100} and {001}. The mineral is associated closely with arsenopyrite, chamosite, liskeardite, pharmacoalumite, pharmacosiderite and quartz. Bettertonite is translucent with a white streak and a vitreous to pearly, somewhat silky lustre. The calculated density is 2.02 g/cm3. Optically, bettertonite is biaxial positive with α = 1.511(1), β = 1.517(1), γ = 1.523(1) (in white light). The optical orientation is X = c, Y= b, Z = a. Pleochroism was not observed. Electron microprobe analyses (average of 4) with H2O calculated on structural grounds and analyses normalized to 100% gave Al2O3 = 29.5, Fe2O3 = 2.0, As2O5= 30.1, SO3 = 1.8, Cl = 0.5, H2O = 36.2. The empirical formula, based on 9 metal atoms is Al5.86Fe0.26(AsO4)2.65(SO4)0.23(OH)9.82Cl0.13(H2O)15.5. Bettertoniteis monoclinic, space group P21/c with unit-cell dimensions (100 K): a = 7.773(2), b = 26.991(5), c = 15.867(3) Å, β = 94.22(3)°. The strongest lines in the powder X-ray diffraction pattern are [d obs in Å(I)(hkl)] 13.648(100)(011); 13.505(50) (020); 7.805(50)(031); 7.461(30)(110); 5.880(20)(130); 3.589(20)(02); 2.857(14)(182). The structure of bettertonite was solved and refined to R 1 = 0.083 for 2164 observed (I > 2σ(I)) reflections to a resolutionof 1 Å. Bettertonite has a heteropolyhedral layer structure, with the layers parallel to (010). The layers are strongly undulating and their stacking produces large channels along [100] that are filled with water molecules. The basic building block in the layers is a hexagonal ring ofedge-shared octahedra with an AsO4 tetrahedron attached to one side of the ring by corner-sharing. These polyoxometalate clusters, of composition [AsAl6O11(OH)9(H2O)5]8–, are interconnected along [100] and [001]by corner-sharing with other AsO4 tetrahedra.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

Access options

Get access to the full version of this content by using one of the access options below.

References

Betterton, J. (2000) Famous mineral localities: Penberthy Croft mine, St. Hilary, Cornwall, England, UK. Journal of Mines and Minerals, 20, 737.Google Scholar
Bevins, R.E., Young, B., Mason., J.S., Manning, D.A.C. and Symes, R.F. (2010) Mineralization of England and Wales, Geological Conservation Review Series, No 36. Joint Nature Conservation Committee, Peterborough [pp. 496-99].Google Scholar
Church, A.H. (1865) Chemical researches on some new and rare Cornish minerals. Journal of the Chemical Society, 18, 259268.CrossRefGoogle Scholar
Farrugia, L.J. (2012) WinGX and ORTEP for Windows: an update. Journal of Applied Crystallography, 45, 849854.CrossRefGoogle Scholar
Gao, Q., Li, F., Wang, Y., Xu, L., Bai, J. and Wang, Y. (2014) Organic functionalization of polyoxometalate in aqueous solution: self-assembly of a new building block of ﹛VMo6O25﹜ with triethanolamine. Dalton Transactions, 43, 941944.CrossRefGoogle ScholarPubMed
Grey, I.E., Mumme, W.G., MacRae, C.M., Caradoc-Davies, T., Price, J.R., Rumsey, M.S. and Mills, S.J. (2013) Chiral edge-shared octahedral chains in liskear-dite, [(Al,Fe)32(AsO4)18(OH)42(H2O)22]-52H2O, an open framework mineral with a pharmacoalumite-related structure. Mineralogical Magazine, 77, 31253135.CrossRefGoogle Scholar
Kampf, A.R., Hughes, J.M., Nash, B.P. and Marty, J. (2014a) New polyoxometalate minerals from the western United States. 21st General Meeting of the International Mineralogical Association, South Africa, 1-5 September, 2014. Abstract Volume p. 374.Google Scholar
Kampf, A.R., Hughes, J.M., Nash, B.P. and Marty, J. (2014b) Kokinosite, Na2Ca2(V10O28)-24H2O, a new decavanadate mineral species from the St. Jude mine, Colorado: crystal structure and descriptive mineralogy The Canadian Mineralogist, 52, 1525.CrossRefGoogle Scholar
Kampf, A.R., Hughes, J.M., Nash, B.P., Wright, S.E., Rossman, G.R. and Marty, J. (2014c) Ophirite, Ca2Mg4[Zn2Mnl+(H2O)2(Fe3+W9O34)2]-46H2O, a new mineral with a heteropolytungstate tri-lacunary Keggin anion. American Mineralogist, 99, 10451051.CrossRefGoogle Scholar
Laugier, J. and Bochu, B. (2000) LMGP-Program for the interpretation of X-ray experiments. INPG/Laboratoire des Matériaux et du Génie Physique. St Martin d'Heres, France.Google Scholar
Long, De-L., Tsunashima, R and Cronin, L. (2010) Polyoxometalates: building blocks for functional nanoscale systems. Angewandte Chemie, International Edition, 49, 17361758.CrossRefGoogle ScholarPubMed
Mandarino, J.A. (1981) The Gladstone-Dale relationship: Part IV. The compatibility concept and its application. The Canadian Mineralogist, 19, 441450.Google Scholar
Lopez, X., Carbo, 11, Bo, C. and Poblet, J.M. (2012) Structure, properties and reactivity of polyoxometalates: a theoretical perspective. Chemical Society Reviews, 41, 75377571.CrossRefGoogle ScholarPubMed
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112122.CrossRefGoogle Scholar
Visser, J.W. (1969) A fully automated program for finding the unit cell from powder data. Journal of Applied Crystallography, 2, 89.CrossRefGoogle Scholar
Walenta, K (1983) Bulachit, ein neues Aluminiumarsenatmineral von Neubulach im nordli-chen Schwarzwald. Aufschluss, 34, 445451.Google Scholar
Supplementary material: File

Grey et al. supplementary material

Tables of anisotropic displacement parameters and observed and calculated structure factors

Download Grey et al. supplementary material(File)
File 2 MB
5
Cited by

Send article to Kindle

To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Bettertonite, [Al6(AsO4)3(OH)9(H2O)5]·11H2O, a new mineral from the Penberthy Croft mine, St. Hilary, Cornwall, UK, with a structure based on polyoxometalate clusters
Available formats
×

Send article to Dropbox

To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

Bettertonite, [Al6(AsO4)3(OH)9(H2O)5]·11H2O, a new mineral from the Penberthy Croft mine, St. Hilary, Cornwall, UK, with a structure based on polyoxometalate clusters
Available formats
×

Send article to Google Drive

To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

Bettertonite, [Al6(AsO4)3(OH)9(H2O)5]·11H2O, a new mineral from the Penberthy Croft mine, St. Hilary, Cornwall, UK, with a structure based on polyoxometalate clusters
Available formats
×
×

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *