The crystal structure of nanpingite-2M2, the Cs end-member of muscovite

Abstract

Other| February 01, 1996 The crystal structure of nanpingite-2M2, the Cs end-member of muscovite Yunxiang Ni; Yunxiang Ni Miami University, Department of Geology, Oxford, OH, United States Search for other works by this author on: GSW Google Scholar John M. Hughes John M. Hughes Search for other works by this author on: GSW Google Scholar American Mineralogist (1996) 81 (1-2): 105–110. https://doi.org/10.2138/am-1996-1-213 Article history first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Yunxiang Ni, John M. Hughes; The crystal structure of nanpingite-2M2, the Cs end-member of muscovite. American Mineralogist 1996;; 81 (1-2): 105–110. doi: https://doi.org/10.2138/am-1996-1-213 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Nanpingite, ideally CsAl2(AlSi3)O10(OH)2, is a Cs end-member dioctahedral mica, crystallizing in C2/c, with a = 9.076(3), b = 5.226(2), c = 21.41(5) Å, and β = 99.48(6)°. The crystal structure of type nanpingite was refined to R = 0.058 using single-crystal X-ray diffraction methods. Nanpingite is a 2M2 polytype dioctahedral mica rather than a 2M2, polytype as reported originally.In comparison with the interlayer cations in common muscovite and paragonite, Cs+ in nanpingite increases the [001] interlayer separation between adjacent 2:1 layers but has little effect on the lateral (a, b) cell dimensions. The existence of the rare 2M2 polytype is attributed to this large interlayer separation, which minimizes the repulsion of the superimposed (along [001]) O anions in the basal planes of neighboring tetrahedral layers. The 2M2 polytype involves ditrigonal prismatic coordination of the interlayer Cs+, in contrast to the octahedral coordination of interlayer K+ and Na+ in muscovite-2M1 and paragonite-2M1. The tetrahedral rotation in nanpingite is the smallest among dioctahedral micas and is also caused by the incorporation of the large interlayer cation Cs+. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.