Fluorapophyllite-(Cs), CsCa4(Si8O20)F(H2O)8, a new apophyllite-group mineral from the Darai-Pioz Massif, Tien-Shan, northern Tajikistan

IF 1.1 4区 地球科学 Q3 MINERALOGY
A. Agakhanov, L. Pautov, A. Kasatkin, V. Y. Karpenko, E. Sokolova, Maxwell C. Day, F. Hawthorne, V. A. Muftakhov, I. Pekov, F. Cámara, S. Britvin
{"title":"Fluorapophyllite-(Cs), CsCa4(Si8O20)F(H2O)8, a new apophyllite-group mineral from the Darai-Pioz Massif, Tien-Shan, northern Tajikistan","authors":"A. Agakhanov, L. Pautov, A. Kasatkin, V. Y. Karpenko, E. Sokolova, Maxwell C. Day, F. Hawthorne, V. A. Muftakhov, I. Pekov, F. Cámara, S. Britvin","doi":"10.3749/canmin.1900038","DOIUrl":null,"url":null,"abstract":"Abstract: Fluorapophyllite-(Cs) (IMA 2018-108a), ideally CsCa4(Si8O20)F(H2O)8, is an apophyllite-group mineral from the moraine of the Darai‐Pioz glacier, Tien‐Shan, Northern Tajikistan. Associated minerals are quartz, pectolite, baratovite, aegirine, leucosphenite, pyrochlore, neptunite, fluorapophyllite-(K), reedmergnerite. Fluorapophyllite-(Cs) is a hydrothermal mineral. It is colourless, it has a vitreous luster and a white streak. Cleavage is perfect, it is brittle and has a stepped fracture. Mohs hardness is 4.5–5. Dmeas. = 2.54(2) g/cm3, Dcalc. = 2.513 g/cm3. Fluorapophyllite(Cs) is unixial (+) with refractive indices (λ = 589 nm) ω = 1.540(2), ε = 1.544(2). It is non-pleochroic. Chemical analysis by electron microprobe gave SiO2 48.78, Al2O3 0.05, CaO 22.69, Cs2O 10.71, K2O 1.13, Na2O 0.04, F 1.86, H2Ocalc. 14.61, –O=F2 –0.78, sum 99.09 wt.%, H2O was calculated from crystal-structure analysis. The empirical formula based on 29 (O + F) apfu, H2O = 8 pfu, is (Cs0.75K0.24)Σ0.99(Ca3.99Na0.01)Σ4(Si8.01Al0.01)Σ8.02 O20.03F0.97(H2O)8, Z = 2. The simplified formula is (Cs,K)(Ca,Na)4(Si,Al)8O20F(H2O)8. Fluorapophyllite-(Cs) is tetragonal, space group P4/mnc, a 9.060(6), c 15.741(11) Å, V 1292.10(19) Å3. The crystal structure has been refined to R1 = 4.31% based on 498 unique (Fo > 4σF) reflections. In the crystal structure of fluorapophyllite-(Cs), there is one [4]T site occupied solely by Si, <T–O > = 1.615 Å. SiO4 tetrahedra link to form a (Si8O20)8– sheet perpendicular to [001]. Between the Si–O sheets, there are two cation sites: A and B. The A site is coordinated by eight H2O groups [O(4) site], A–O(4) = 3.152(4) Å; the A site contains Cs0.75K0.24o0.01, ideally Cs apfu. The Cs–O bondlength of 3.152 Å is definitely larger than the K–O bondlength of 2.966–2.971 Å in fluorapophyllite-(K), KCa4(Si8O20)F(H2O)8. The [7]B site contains Ca3.99Na0.01, ideally Ca4 apfu; <B–φ> = 2.420 Å (φ = O, F, H2O). The Si–O sheets connect via A and B polyhedra and hydrogen bonding; two H atoms have been included in the refinement. Fluorapophyllite-(Cs) is isostructural with fluorapophyllite-(K). Fluorapophyllite-(Cs) is a","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"57 1","pages":"965-971"},"PeriodicalIF":1.1000,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900038","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Canadian Mineralogist","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.3749/canmin.1900038","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MINERALOGY","Score":null,"Total":0}
引用次数: 2

Abstract

Abstract: Fluorapophyllite-(Cs) (IMA 2018-108a), ideally CsCa4(Si8O20)F(H2O)8, is an apophyllite-group mineral from the moraine of the Darai‐Pioz glacier, Tien‐Shan, Northern Tajikistan. Associated minerals are quartz, pectolite, baratovite, aegirine, leucosphenite, pyrochlore, neptunite, fluorapophyllite-(K), reedmergnerite. Fluorapophyllite-(Cs) is a hydrothermal mineral. It is colourless, it has a vitreous luster and a white streak. Cleavage is perfect, it is brittle and has a stepped fracture. Mohs hardness is 4.5–5. Dmeas. = 2.54(2) g/cm3, Dcalc. = 2.513 g/cm3. Fluorapophyllite(Cs) is unixial (+) with refractive indices (λ = 589 nm) ω = 1.540(2), ε = 1.544(2). It is non-pleochroic. Chemical analysis by electron microprobe gave SiO2 48.78, Al2O3 0.05, CaO 22.69, Cs2O 10.71, K2O 1.13, Na2O 0.04, F 1.86, H2Ocalc. 14.61, –O=F2 –0.78, sum 99.09 wt.%, H2O was calculated from crystal-structure analysis. The empirical formula based on 29 (O + F) apfu, H2O = 8 pfu, is (Cs0.75K0.24)Σ0.99(Ca3.99Na0.01)Σ4(Si8.01Al0.01)Σ8.02 O20.03F0.97(H2O)8, Z = 2. The simplified formula is (Cs,K)(Ca,Na)4(Si,Al)8O20F(H2O)8. Fluorapophyllite-(Cs) is tetragonal, space group P4/mnc, a 9.060(6), c 15.741(11) Å, V 1292.10(19) Å3. The crystal structure has been refined to R1 = 4.31% based on 498 unique (Fo > 4σF) reflections. In the crystal structure of fluorapophyllite-(Cs), there is one [4]T site occupied solely by Si, = 1.615 Å. SiO4 tetrahedra link to form a (Si8O20)8– sheet perpendicular to [001]. Between the Si–O sheets, there are two cation sites: A and B. The A site is coordinated by eight H2O groups [O(4) site], A–O(4) = 3.152(4) Å; the A site contains Cs0.75K0.24o0.01, ideally Cs apfu. The Cs–O bondlength of 3.152 Å is definitely larger than the K–O bondlength of 2.966–2.971 Å in fluorapophyllite-(K), KCa4(Si8O20)F(H2O)8. The [7]B site contains Ca3.99Na0.01, ideally Ca4 apfu; = 2.420 Å (φ = O, F, H2O). The Si–O sheets connect via A and B polyhedra and hydrogen bonding; two H atoms have been included in the refinement. Fluorapophyllite-(Cs) is isostructural with fluorapophyllite-(K). Fluorapophyllite-(Cs) is a
塔吉克斯坦北部天山Darai Pioz地块的一种新的脱叶石群矿物——氟脱叶石-(Cs),CsCa4(Si8O20)F(H2O)8
摘要:氟叶绿石-(Cs)(IMA 2018-108a),理想情况下为CsCa4(Si8O20)F(H2O)8,是塔吉克斯坦北部天山Darai‐Pioz冰川冰碛中的一种叶绿石群矿物。伴生矿物有石英、果胶岩、白榴石、赤铁矿、隐霞石、烧绿石、镎石、萤石-(K)、芦苇镁石。萤石是一种热液矿物。它无色,有玻璃光泽和白色条纹。解理是完美的,它很脆,有阶梯状断裂。莫氏硬度为4.5–5。D测量=2.54(2)g/cm3,Dcalc.=2.513克/立方厘米。萤石(Cs)为单轴(+),折射率(λ=589nm)ω=1.540(2),ε=1.544(2)。电子探针化学分析得到SiO2 48.78,Al2O3 0.05,CaO 22.69,Cs2O 10.71,K2O 1.13,Na2O 0.04,F 1.86,H2Ocalc。14.61,–O=F2–0.78,总和99.09 wt.%,H2O通过晶体结构分析计算。基于29(O+F)apfu,H2O=8pfu的经验公式为(Cs0.75K0.24)∑0.99(Ca3.99Na0.01)∑4(Si8.01Al0.01)∑8.02 O20.03F0.97(H2O)8,Z=2。简化公式为(Cs,K)(Ca,Na)4(Si,Al)8O20F(H2O)8。萤石-(Cs)是四方晶系,空间群P4/mnc,a 9.060(6),c 15.741(11)Å,V 1292.10(19)Å3。基于498个独特的(Fo>4σF)反射,晶体结构被细化为R1=4.31%。在荧光体-(Cs)的晶体结构中,有一个[4]T位点仅被Si占据,=1.615Å。SiO4四面体连接形成垂直于[001]的(Si8O20)8–片。在Si–O片之间,有两个阳离子位点:A和B。A位点由八个H2O基团[O(4)位点]配位,A–O(4)=3.152(4)Å;A位点含有Cs0.75K0.24o0.01,理想情况下为Cs-apfu。3.152Å的Cs–O键长肯定大于氟叶绿柱石-(K),KCa4(Si8O20)F(H2O)8中2.966–2.971Å的K–O键长度。[7]B位点含有Ca3.99Na0.01,理想情况下为Ca4-apfu;=2.420Å(φ=O,F,H2O)。Si–O片通过A和B多面体和氢键连接;两个H原子已经被包括在细化中。萤石-(Cs)与萤石-(K)是同结构的。萤石-(Cs)是一种
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Canadian Mineralogist
Canadian Mineralogist 地学-矿物学
CiteScore
2.20
自引率
22.20%
发文量
45
审稿时长
4-8 weeks
期刊介绍: Since 1962, The Canadian Mineralogist has published papers dealing with all aspects of mineralogy, crystallography, petrology, economic geology, geochemistry, and applied mineralogy.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信