Weinebeneite, CaBe 3 (PO 4 ) 2 (OH) 2 . 4H 2 O, a new mineral species; mineral data and crystal structure
Weinebeneite, CaBe 3 (PO 4 ) 2 (OH) 2 . 4H 2 O, a new mineral species; mineral data and crystal structure
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DOI：
10.1127/ejm/4/6/1275
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发表时间：
1992-12
影响因子：
2.1
通讯作者：
Franz Walter
中科院分区：
文献类型：
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作者：
Franz Walter
Weinebeneite是产于奥地利克恩顿州Koralpe高级变质岩中的锂辉石伟晶岩中的一种新矿物。它作为次生矿物出现在小裂缝中，与水碳镁石、蔷薇辉石和铀云母共生。它形成透明、无色、玻璃状、片状晶体，直径达0.1 x 0.3 x 0.5 mm，周围是直径达20 mm的他形微钠石莲座。它很脆，有碎裂的裂缝。莫氏硬度为3- 4 l dmeas。2.15（4）2.17g/cm ~ 3。在光学性质上，微碳镁石为双轴正性，但接近单轴性，其2Kγ测量值。< 10; na= 1.520，Wβ= 1.520，Wγ= 1.530（589 nm）; Z：c-42，锐角β。钠镁矾为单斜晶系，a= 11.897（2），B= 9.707（1），c= 9.633（1），B= 95.76（1），V= 1106.8（3），Z= 4。X-射线粉末衍射图的三条最强线为[d（λ），（hkt），I]：2.513，（223），100; 3.421，（221），70; 5.92，（200），60。电子探针、原子吸收、电子能量损失谱分析和结构精修的综合结果产生式Cao。99Be3. 02P1。97 O7 88（OH）2。n. 4 H2O（基于O= 14）或理想情况下，CaBe 3（PO 4）2（OH）2。4H2O。名称引用类型位置。用1341个独立反射点，用直接法解出了该矿物的晶体结构，并将其空间群Cc修正为R= 0.043和Rw= 0.044。微铍石是一种骨架磷酸铍，其结构的空腔中含有钙和水分子。铍四面体和磷四面体共用角，形成由4环和8环组成的层。平行于（100）取向的两个叠加的4.82二维网络通过B/2平移相关，通过额外的铍四面体连接，产生了具有不寻常排列的框架：两个三元环中的五个四面体共享一个四面体。Weinebeneite是第一个报道的含有三元环的框架铍磷酸盐的例子。钙位于平行于[001]的通道中，由骨架的三个O原子和四个水分子配位。其中一个水分子在两个位点上显示出明显的位置无序。
Weinebeneite is a new mineral species from a spodumene pegmatite at Weinebene that occurs in the high-grade metamorphic rocks of Koralpe, Carinthia, Austria. It occurs in small fractures as a secondary mineral associated with fairfieldite, roscherite and uralolite. It forms clear, colorless, vitreous, platy crystals up to 0.1 x 0.3 x 0.5 mm surrounding rosettes of xenomorphic weinebeneite up to 20 mm in diameter. It is brittle with a splintery fracture. Mohs' hardness IS 3-4l dmeas.~~ 2.15 (4) g/cm3 and dealer1 2.17 g/cm3. Optically, weinebeneite is biaxial positive but nearly uniaxial with 2Kγmeas.< 10; na= 1.520, Wβ= 1.520, Wγ= 1.530 (589 nm); Z: c-42 in acute angle β. Weinebeneite is monoclinic, a= 11.897 (2), b= 9.707 (1), c= 9.633 (1) Å, b= 95.76 (1), V= 1106.8 (3) Å3 and Z= 4. The three strongest lines of the X-ray powder diffraction pattern are [d (Å),(hkt), I]: 2.513,(223), 100; 3.421,(221), 70; 5.92,(200), 60. The combined results of electron-microprobe, atomic absorption, electron energy-loss-spectroscopy analyses and structure refinement yield the formula Cao. 99Be3. 02P1. 97 O7. 88 (OH) 2. n. 4H2O (based on O= 14) or, ideally, CaBe3 (PO4) 2 (OH) 2. 4H2O. The name refers to the type locality. The crystal structure of weinebeneite has been solved by direct methods and refined in space group Cc to R= 0.043 and Rw= 0.044 using 1341 independent reflections. Weinebeneite is a framework beryllophosphate with calcium and water molecules in the cavities of the structure. The beryllium-and phosphorus-tetrahedra share corners forming a layer consisting of 4-and 8-rings. Two superimposed 4.82 2D nets oriented parallel to (100) and related by translation in b/2 are connected by additional beryllium tetrahedra, giving rise to a framework with an unusual arrangement: five tetrahedra in two three-membered rings share a tetrahedron. Weinebeneite is the first reported example of a framework beryllophosphate containing three-membered rings. Calcium is located in chan nels parallel to [001], coordinated by three O atoms of the framework and four water molecules. One of the water molecules displays apparent positional disorder over two sites.