异性石中平面四配位Fe^2＋的穆斯堡尔谱研究

除硅铁钡矿之处，性石是迄今仅知的另一种含有平面四配位Ｆｅ＾２＋的矿物，异性石晶体样品为玫瑰色，透明，有油脂光泽，取自一花岗岩标本，异性石中平面四配位Ｆｅ＾２＋的穆斯堡尔参数：化学位移＝０．７８５（ｍｍ／ｓ）（相对天然铁），四极矩分裂＝０．４１９（ｍｍ／ｓ），明显地低于大多数硅酸矿物中的Ｆｅ＾２＋，但和硅铁钡矿的Ｆｅ＾２＋十分相近，本文对硅酸盐矿物Ｆｅ＾２＋的穆斯堡尔参数与配位数之间的关系做了讨论。     

硅酸盐矿物中Fe^2＋离子同质异能位移与平均有效离子半径之间的关系

同质异能位移是矿物的重要穆斯鲍尔参数之一，本文首次讨论了硅酸盐矿物中硅酸盐矿物中Ｆｅ＾２＋离子的同质异能位移ＩＳ与离子的平均有效半径ｒ↑－之间的关系，发现它们之间的关系可以用一简单线性方程ＩＳ（ｍｍ／ｓ）＝０．５８ｒ↑－＋０．６９５来表示，其相关系数Ｒ＝０．９３。本文还根据同质异能位移与原子核处ｓ电子密度│ψＡ（０）│＾２之间的关系，定性地解释了上述线性方程。     

一种硼酸盐的新矿物─—袁复礼石

袁复礼石是一种Ｍｇ、Ｆｅ￣（３＋）、Ａｌ和Ｔｉ的硼酸盐新矿物，发现于辽宁省宽甸县砖庙硼矿区。该矿物黑色，近不透明，金刚光泽一半金属光泽。反射色亮灰，内反射深红褐色。非均质性弱，偏光色红褐。晶体呈细柱状，０．１×０．２×１ｍｍ。晶体化学式为：空间群：Ｈ＝５－６，ＶＨＮ＿（５０）＝８４３ｋｇ／ｍｍ￣２。｛１００｝解理完全。红外光谱吸收谱带为：１３８７，１２１０，１０２４，９５１，７３３，６００，５１０和４０８ｃｍ￣（－１）。穆斯堡尔谱证明，以三价铁为主，二价铁较少。Ｆｅ￣（３＋）占据Ｍ（１）晶位，Ｆｅ￣（２＋）占据Ｍ（１）和Ｍ（２）晶位。袁复礼石为硼钛镁石的富Ｆｅ￣（３＋）类似物。     

铁尖晶橄榄石的穆斯堡尔谱研究

本文使用穆斯堡尔效应研究了在高温高压下合成的铁橄榄石和铁尖晶橄榄石。２９８Ｋ温度下铁橄榄石的穆斯堡尔谱由一组双峰组成，它被指派给Ｆｅ＾２＋（Ｍ１，Ｍ２）离子。２９８Ｋ温度下铁尖晶橄榄石的穆斯堡尔谱由三组双峰组成，其中两组双峰指派给八面体位置Ｂ上的Ｆｅ＾２＋，另一组双峰归为四面体位置Ａ上的Ｆｅ＾３＋，两组Ｆｅ＾２＋双峰的同质异能迁移近似相等而四极分裂不同，Ｓｉ原子在八面体位置上的占有率为６％～１０％     

锡铁山石晶体结构中Fe3+的两种亚晶位

对产于青海锡铁山铅锌矿氧化带中的锡铁山石进行了５７Ｆｅ穆斯堡尔谱的研究，在晶体结构分析的基础上进行了谱峰的重新解释，发现由于配位Ｃｌ－离子无序占位引起Ｆｅ３＋离子所占配位八面体的畸变，形成了Ｆｅ３＋的两种亚晶位，并根据结构数据指定了这两种亚晶位各自形成的四极双峰。     

蒙脱石中铁的赋存状态的研究

通过对徐闻、三水、高州等地五个样品的Ｘ射线衍射分析，化学全分析，分析它们为含铁量不同的蒙脱石，层间可交换阳离子主要为Ｃａ＾２＋。几个样品穆斯堡尔谱表明铁主要以Ｆｅ＾３＋的形式存在，含铁量较高的样品ＸＧＡ、ＸＳＡ、ＳＳ的谱可以拟合出Ｆｅ＾３＋的二对四级双峰，表明铁在蒙脱石中占据两种不等同的八面体位置。     

黄铁矿的穆斯堡尔谱特征及其机理分析

本区金矿中黄铁矿的Ｍｏ谱测试和综合分析表明，主要穆斯堡尔参数的变化与含金性之间存在有一定的关系。主要表现为，黄铁矿的Ｉ．Ｓ．值与含金性间呈明显的负相关。Ｏ．Ｓ．值与含金性间则呈明显的正相关，且Ｏ．Ｓ．值随着（Ａｕ＋Ａｓ）／（Ｃｏ＋Ｎｉ）原子数比值的增大而增大。这是由于Ａｕ＋取代Ｆｅ２＋进入黄铁矿晶格使其结构产生畸变所致。置换时电荷补偿可通过两个途径来实现，其一是Ａｕ＋（Ｃｏ３＋、Ｎｉ３＋）→２Ｆｅ２＋，其二是Ａｓ３＋＋Ａｕ＋→２Ｆｅ２＋。     

同步辐射X射线吸收谱及其在矿物学、地球化学中的应用

矿物谱学是目前矿物学,甚至岩石学、地球化学中方兴未艾的一个研究领域。但现在常用于矿物学研究的谱学方法都有一定的局限性,如穆斯堡尔谱只能研究穆斯堡尔核,通常为５７Ｆｅ、１１９Ｓｎ。可见吸收光谱限于研究能产生颜色的过渡金属离子或色心,电子顺磁共振谱要求被...     

西藏罗布莎铬铁矿穆斯堡尔谱特征及其地质意义

讨论了在温度为３００Ｋ条件下罗布莎铬铁矿穆斯堡尔谱的特征。根据谱形将全谱分民三套双峰,其中中第Ⅰ、第Ⅱ 由四面体中的Ｆｅ＾２＋产生的,第Ⅲ套是由八面体中Ｆｅ＾３＋产生的;总结出了中心位移值与铬铁矿平衡压力以及四级分裂值（ＱＳ）,铬铁矿平衡温度之间的关系;探讨了铬铁矿的成国在。研究结果表明,铬铁矿穆斯堡尔谱的两上重要参数δ和ＱＳ在铬铁矿成矿预测中可以 作为矿物学标型特征来推测矿床的成因,参数的质量达     

辽宁宽甸地幔矿物三阶铁的穆斯堡尔谱测定及意义

利用穆斯堡尔谱仪对辽宁宽甸地幔岩包体中的矿物进行了三阶铁的测定,测试结果与国内外已发表的数据接近。Ｆｅ＾３＋／∑Ｆｅ比值分别为：斜方辉石０．０６６￣０．１９６,单斜辉石０．２１６￣０．３４４,尖晶石０．２８３￣０．２９９,石榴石０．０５７￣０．２２３。依据电价平衡原理计算的Ｆｅ＾３＋含量受Ｓｉ＾４＋、Ａｌ＾３＋和Ｃｒ＾３＋的电子探针分析误差影响很大。根据地幔矿物的电子探针分析结果计算平衡温度、压力     

Spectroscopic standard for tetrahedrally coordinated ferric iron: γ LiAlO2:Fe3+

γ LiAlO₂ doped with Fe³⁺ in the tetrahedral site has been examined by extended X-ray absorption fine structure (EXAFS) analysis, and Mössbauer and optical spectroscopy. The isomer shift (IS) is ?0.026 mm/s (Fe-Pd); the quadrupole splitting (QS) is 0.62 mm/s. Anisotropic optical absorption is prominent at ～391, 452, and 463 nm. The K-edge absorption spectrum shows a prominent absorption near 7,113 ev typical of tetrahedrally coordinated Fe³⁺.     

黝锡矿的119Sn和57Fe穆斯堡尔谱研究

本文收集了我国南方4个产地的黝锡矿样品,使用电子探针、X射线衍射、~(119)Sn、~(57)Fe穆斯堡尔谱等测试方法测试。X射线衍射结果,黝锡矿的晶胞参数为:a=5.4531(5)?,c=10.7470(7)?,四方晶系,空间群I42m。4个不同产地的黝锡矿的Sn、Fe穆斯堡尔谱测量表明:锡的I·S值为1.34—1.49mm/s,Q·S值为0.36—0.50mm/s,为四面体的Sn~(4+);铁的I·S值为0.588—0.596mm/s,Q·S值为2.900—2.911mm/s,为四面体的Fe~(2+)。Sn、Fe离子仅占据一种结晶学位置。这些黝锡矿富Zn,Zn以类质同象置换Fe。     

Intracrystalline fractionation of Fe in synthetic (Fe, Mg, Zn) - bearing staurolite: a Mössbauer spectroscopic study

⁵⁷Fe-Mössbauer spectra of eleven Fe-Mg-bearing staurolite samples, synthesized at 5, 20 and 25 kbar and 680°C, ranging in composition from x_Fe?=1.00 to x_Fe?=0.15, and of two Zn-Fe-bearing staurolite samples, synthesized at 20 kbar and 700°C with x_Fe?=0.10 and x_Fe?=0.32 were collected at room temperature. The spectra reveal that about 80% of Fe_tot (in case of Fe-Mg-bearing staurolite) and about 70% of Fe_tot (in case of Fe-Zn-bearing staurolite) are located as Fe²⁺ at the three subsites Fe1, Fe2 and Fe3 of the tetrahedral T2-site. The refinement of the spectra results in almost identical values for the isomer shift (IS) (±1.0 mm/s) but significantly different values for the quadropole splitting (QS) for the three subsites which is in accordance with the different distortions of these sites. About 8% of Fe_tot (in case of Fe-Mg-bearing staurolite) and 13% of Fe_tot (in case of Fe-Zn-bearing staurolite) are located as Fe²⁺ at the octahedral M4 site, while the remainder percents of Fe_tot indistinguishably occur as Fe²⁺ at the octahedral M1 and M2 sites of the kyanite-like part of the structure. Within the whole Fe-Mg-staurolite solid solution series the Mössbauer parameters QS of the sites M4 and (M1, M2) vary systematically with composition whereas IS remains constant. There is a high negative correlation of the total Mg-content with Fe-occupation of all the Fe-bearing sites indicating a continuous substitution of Fe²⁺ by Mg on all these sites. Synthetic Fe-staurolites show no increasing occupation of the octahedral sites by two-valent cations with pressure, as was assumed by several authors.     

巨晶普通辉石的M1位分裂

巨晶普通辉石的Ｍ１位分裂李一良，支霞臣，李玉芝，李铁，张裕恒（中国科学技术大学，合肥２３００２６）关键词巨晶辉石，Ｍ１位分裂，面积约束法，近邻边效应，Ｔ位铁单斜辉石的穆斯堡尔谱学研究历时已久。但由于其晶体结构和成份的复杂性、化学不均一性及出溶现象等［...     

Glass-iron-clay interactions in a radioactive waste geological disposal: An integrated laboratory-scale experiment

Glass-iron-clay setups were reacted at 90 °C for 6-18 months to investigate the coupled interactions between glass alteration, Fe corrosion and clay transformation. The reacted interfaces were probed at the microscopic level using complementary characterization methods (scanning electron microscopy coupled with energy-dispersive X-ray analysis, micro-Raman spectroscopy, micro X-ray diffraction, micro X-ray fluorescence spectroscopy, and micro X-ray absorption near-edge structure spectroscopy). The 10-μm thick Fe foil was fully corroded within 10 months, exposing glass to the pore solution. Iron corrosion led to the formation of a layer containing mostly magnetite, siderite and Fe-rich phyllosilicates with one tetrahedral and one octahedral sheet (TO) or two tetrahedral and one octahedral (TOT) sheet per layer. The clay in contact with this corrosion layer was enriched in siderite (FeCO₃). Glass alteration resulted in the formation of a gel layer whose thickness increased with reaction time (from 20 μm after 6 months to 80 μm after 18 months) and a thin layer of secondary precipitates that concentrated lanthanides, P, and Mo. Assuming conservative behavior of Zr, the Si molar concentration in the gel is about 57% that in the glass. Glass dissolution remained at a rate close to the initial dissolution rate r₀. The data are consistent with glass dissolution sustained by the uptake of dissolved Si and charge-compensating cations on secondary (corrosion) products, thus maintaining the gel porosity open and facilitating the leaching of easily soluble elements.     

The A and B mica layers and the crystal structure of sheet silicates

A discussion of the transition from the ideal hexagonal mica structure to the ideal ditrigonal one, leads to the conclusion that the single mica layer may have two different structures (labelled A and B). The recent literature data show that both the A and B structures have been detected in some triocahedral layer lattice silicates found in nature. An examination of the structural stability of the A and B structures suggests that the last one may not be realized by dioctahedral layer lattice silicates. The concept of two structurally different mica layers, which however have the same lattice constants, greatly improves the understanding of polymorphism and twin laws in layer lattice silicates.The structural features of the tetrahedral sheet, octahedral sheet and interlayer region are carefully examined. Thus we can reach the following conclusions: the tetrahedal sheet is not entirely free to reduce its lateral dimensions by the mechanism of tetrahedal rotation owing to the repulsion among O_bas atoms; the octahedral sheet in layer lattice silicates, may increase or reduce its lateral dimensions as compared to the lateral dimensions it has in the hydroxide minerals; the interlayer region is characterized by a regular octahedral coordination of the O_bas around the interlayer cation. On the ground of these conclusions, new structural models for some selected layer lattice silicates are proposed.Notations O_bas basal oxygen atoms of the (Al, Si)O₄ tetrahedra - O_ap apical oxygen atoms of the (Al, Si)O₄ tetrahedra - b _tetr b dimension which the tetrahedral sheet would assume if unconstrained - b _oct b dimension which the octahedral sheet has in the hydroxide minerals - b _obs observed value of b - c _oct ^* thickness of the octahedral sheet - d _o distance between an octahedral cation and an O_ap atom - d _int distance between an interlayer cation and an O_bas atom - average tetrahedral rotation from ideal hexagonal symmetry     

Gas-chromatographic investigations on dimethyldioctadecyl ammonium derivatives of different clay minerals

The gas-chromatographic behaviour (selectivity performance for cyclohexanebenzene and m-, p-xylenes pairs separation) of dimethyldioctadecylammonium complexes with kaolinite, fire-clay, halloysite, attapulgite, hectorite and various montmorillonites, nontronites and vermiculites has been investigated. The obtained data indicate the influence of specific surface and charge density on relative retention value (), and of substitution location (tetrahedral versus octahedral sheet) within the clay lattice on selectivity. Hence, derivatives with nontronites and vermiculites, that is the clay minerals where the principal lattice substitutions are predominantly occurring within the tetrahedral sheet and possessing the highest surface charge density, are very effective sorbents for gas-chromatographic use. The application of gas-chromatography as investigation tool of clays surface is suggested.