The crystal structure of waylandite from Wheal Remfry, Cornwall, United Kingdom

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• 作者：Stuart J. Mills ; Anthony R. Kampf ; Mati Raudsepp and William D. Birch
• 刊名：Mineralogy and Petrology
• 出版年：2010
• 出版时间：November 2010
• 年：2010
• 卷：100
• 期：3-4
• 页码：249-253
• 全文大小：305.2 KB

文摘

Sr- and Ca-rich waylandite, ( Bib>0.54b>Srb>0.31b>Cab>0.25b>Kb>0.01b>Bab>0.01b> )b>S1.12b>Hb>0.18b>( Alb>2.96b>Cub>0.02b> )b>S2.98b>[ ( Pb>0.97b>Sb>0.03b>Sib>0.01b> )b>S1.00b>Ob>4b> ]b>2b>( OH )b>6b> {\left( {{\hbox{B}}{{\hbox{i}}_{0.{54}}}{\hbox{S}}{{\hbox{r}}_{0.{31}}}{\hbox{C}}{{\hbox{a}}_{0.{25}}}{{\hbox{K}}_{0.0{1}}}{\hbox{B}}{{\hbox{a}}_{0.0{1}}}} \right)_{\Sigma 1.12}}{{\hbox{H}}_{0.{18}}}{\left( {{\hbox{A}}{{\hbox{l}}_{{2}.{96}}}{\hbox{C}}{{\hbox{u}}_{0.0{2}}}} \right)_{\Sigma 2.98}}{\left[ {{{\left( {{{\hbox{P}}_{0.{97}}}{{\hbox{S}}_{0.0{3}}}{\hbox{S}}{{\hbox{i}}_{0.0{1}}}} \right)}_{\Sigma 1.00}}{{\hbox{O}}_4}} \right]_2}{\left( {\hbox{OH}} \right)_6} , from Wheal Remfry, Cornwall, United Kingdom has been investigated by single-crystal X-ray diffraction and electron microprobe analyses. Waylandite crystallises in space group R [`3] \overline 3   m, with the cell parameters: a = 7.0059(7) ?, c = 16.3431(12) ? and V = 694.69(11) ?3. The crystal structure has been refined to R b>1b> = 3.76 % . Waylandite has an alunite-type structure comprised of a rhombohedral stacking of (001) composite layers of corner-shared AlOb>6b> octahedra and POb>4b> tetrahedra, with (Bi,Sr,Ca) atoms occupying icosahedrally coordinated sites between the layers.