Classification of eudialyte-group minerals
Classification of eudialyte-group minerals
复制标题
真解体矿物的分类
DOI：
--
复制
发表时间：
2012
影响因子：
0.7
通讯作者：
N. Chukanov
中科院分区：
文献类型：
--
作者：
R. Rastsvetaeva;N. Chukanov
根据国际矿物学协会新矿物、命名和分类委员会的规定，新矿物种的定义应根据新元素在一个或几个关键位置占优势的一般晶体化学原理。到目前为止，已根据这一建议批准了25种正渗析物类矿物。此外，50个样品（包括潜在的新物种的eudialyte组）进行了研究，使用红外光谱和X射线衍射。新的数据需要修改和补充现行的系统学的eudialyte组。eudialyte型结构包含独特的片段，涉及物种形成的关键位点。本研究中开发的晶体化学分类基于考虑以下特征的分层原则（按其分类等级的降低顺序列出）：
（i）晶体结构的简单或模块特征和c参数值（对于12层和24层矿物分别约为30和60 μ m）（ii）由八面体环中的阳离子排序确定的对称性，即，M（1）位划分为M（1a）和M（1b）的可能性;（iii）不同组分在M（2）位上的分布;（iv）含水量（将常渗析矿物分为低含水和高含水两类，Na >（H2O + H3 O）和Na <（H2O + H3 O））。
12层矿物被细分为eudialyte和oneillite类型的物种。这两种类型的进一步细分为亚型是基于八面体，四面体，或在九元Si，O-环中心的M（3）和M（4）位点的空位和这些变体的不同组合的优势。类型和亚型术语在这里都是在晶体化学意义上使用的。在24层矿物中，第一次细分是基于水化程度;第二次细分为子类型考虑了不同模块（地板）的Z八面体中主要成分（Zr + Zr，Ti + Ti或Zr + Ti）的组合。属于不同晶体化学分类群的各种常渗析族矿物的简要特征。
AbstractAccording to the rules accepted by the Commission on New Minerals, Nomenclature and Classification, International Mineralogical Association, the definition of a new mineral species within the eudialyte group should be based on the general crystal chemical principle of the predominance of a new element at one or several key sites. To date, 25 minerals of the eudialyte group have been approved in line with this recommendation. Additionally, 50 samples (including potential new species of the eudialyte group) have been investigated using IR spectroscopy and X-ray diffraction. The new data require the modification and complementation of the current systematics of the eudialyte group. The eudialyte-type structures contain unique fragments that involve species-forming key sites. The crystal chemical classification that develops in this study is based on the hierarchical principle that takes into account the following features (listed in order of their lowering classification rank):
(i)simple or modular character of the crystal structure and value of c parameter (about 30 and 60 Å for 12- and 24-layer minerals, respectively)(ii)symmetry determined by cation ordering in the octahedral ring, i.e., the possibility of dividing site M(1) into M(1a) and M(1b)(iii)the distribution of different components into five M(2) square-based sites(iv)the water content (subdivision of the eudialyte-group minerals into low-and high-hydrous species with Na > (H2O + H3O) and Na < (H2O + H3O), respectively.
The 12-layer minerals are subdivided into eudialyte- and oneillite-type species. The further subdivision of these two types into subtypes is based on the predominance of octahedra, tetrahedra, or vacancies at sites M(3) and M(4) in the centers of nine-membered Si,O-rings and different combinations of these variants. Both type and subtype terms are used here in the crystal chemical sense. Among 24-layer minerals, the first subdivision is based on the degree of hydration; the second subdivision into subtypes takes into account combinations of predominant components (Zr + Zr, Ti + Ti, or Zr + Ti) in Z octahedra of different modules (floors). Various eudialyte-group minerals that belong to different crystal chemical taxons are briefly characterized.