权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Synthesis and Characterization of Hollandite Type Compounds

镁锰矿型化合物的合成与表征

基本信息

批准号：
60540521
负责人：
OHSATO Hitoshi
金额：
$ 0.96万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60540521/
关键词：
hollandite type compounds cryptomelane manganese dioxide one dimensional tunnel structure host and gest cations DTA,TGA occupncy 合成

项目摘要

Chemical formula of hollandite type compounds is generally <A_x(M^(3+)M^(2+))_yM_(8-y)O_(16)> (0<x<2). Cations M (Mn, Ti, Fe, Al etc.) locate on the octahedral sites of oxygen and construct double strings of octahedron. The four strings make one dimensional tunnel structure formed tetragonal prism. Large cations A (K,Na,Ba etc.) occupy on the pseudo-cube sites of oxygen. It is expected that this type compounds are used for one dimensional ion conductor, absorbent and SYNROC which trap radioactive waste large ions (Cs, etc.). In this work, crystals of this type compound were synthesized and were characterized for understanding of the tunnel. In the first year, hollandite ( <Ba_xMn_8O_(16)> , 1.23<x<1.36) was synthesized for the first time in the air up to 880 C by means of solid state reaction. Although the compound exists in nature, it had never been synthesized so far. The occupancy of hollandite was changed from low to high occupancy according as the temperature increases. This phenomena had been observed in cryptomelane. In the next year, solid solutions of cryptomelane ( <K_xMn_8O_(16)> , 1.0<x<2.0) were synthesized and the relationship between the compositions and the decomposition temperatures of them was derived by DTA. The occupancy of cryptomelane with high occupancy was decreased up to about 60% in the hot water for three weeks. The occupancy of K-ion sites of natural cryptomelane is about 50% in nature. Perhaps natural cryptomelane was washed out by natural water and then the occupancy of K-ion sites fell to half. These informations were very available for understanding the tunnel structure.

钙铝石型化合物的化学式一般为<A_x（M^（3+）M^（2+））_yM_（8-y）O_（16）>（0<x<2）。阳离子M（Mn、Ti、Fe、Al等）位于氧的八面体位置上，构成八面体的双弦。四根弦构成一维隧道结构，形成四棱柱体。大阳离子A（K、Na、Ba等）占据氧的准立方体位置。这类化合物有望用作一维离子导体、吸收剂和捕获放射性废物大离子（Cs等）的SYNROC。在这项工作中，这种类型的化合物的晶体的合成和表征的隧道的理解。第一年，首次在空气中，用固相反应法，在880 ℃下合成了钙钛矿（<Ba_xMn_8O_（16）>，1.23<x<1.36）。虽然这种化合物存在于自然界中，但迄今为止从未被合成过。随着温度的升高，锰的占有率由低到高变化。这一现象在锰钾矿中已被观察到。第二年，合成了锰钾矿（<K_xMn_8O_（16）>，1.0<x<2.0）的固溶体，用差热分析（DTA）法测定了它们的组成与分解温度的关系。高占有率的锰钾矿在热水中三周的占有率下降到约60%。天然锰钾矿中钾离子占据率约为50%。可能是天然锰钾矿被天然水冲走，然后K离子位点的占有率下降到一半。这些信息对于了解隧道结构是非常有用的。