ISSN:0232-1300    

DOI:10.1002/crat.2170210625

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170210626

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170210627

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170210628

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170210629

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170210630

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractNatural scolecite is converted into analcime type zeolite by hydrothemal method at 180 °C at autogeneous pressure for 24 to 160 hours growth runs. Mordenite is detected in the final product. Cube and spheroid crystals of the products are illustrated and described. Crystals synthesized are characterized by X‐ray diffraction, infrared spectroscopy EDAX and scanning electron microscopy. Particle size is estimated as 20–60 microns, induction period for nucleation as 12 hrs, and lattice parameter of cube crystals as 13.70 Å. Mechanism of growth, influence of anions and duration of growth etc. are discussed. It is established that the crystals grow in the system Na2OAl2O3

ISSN:0232-1300    

DOI:10.1002/crat.2170210602

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractX‐Ray diffraction and neutronographical studies on the crystal structure of the perovskitelike compounds A(Cu1−xMnx)Mn4O12have been undertaken. It has been shown that the samples with 50% of Mn3+in the octahedral sites have a cubic unit cell, while the samples with higher Mn3+composition may have a monoclinic or rhombohedral unit cell. The temperature increase raises the symmetry to the cubic one. The concentration ranges with different symmetry type have been determined. The lowering of the symmetry of the unit cell is due to the cooperative Jahn‐Teller e

ISSN:0232-1300    

DOI:10.1002/crat.2170210603

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe paper informs on the formation of the garnets Y3Fe5O12, Y3Al5O12and Gd3Ga5O12as primary phase in the ternary solvent mixtures PbOPbF2B2O3and PbOMoO3B2O3. There are correlations with formerly measured oxygen ion concentrations (OIC) in the solvents:ieach garnet grows in a special region of the OIC, the phase boundaries are parallel to the lines of constant OIC andiithe garnet solubility increases distinctly with decreasing OIC. This emphasizes the important role of the oxygen ions for the garnet formation.Solubility models are discussed taking into consideration both previous and present results. We conclude that the garnet formation is described best by a model reaction of the type\documentclass{article}\pagestyle{empty}\begin{document}$$3{\rm RE}^{{\rm 3 + }} \, + \,2{\rm M}^{{\rm 3 + }} \, + \,{\rm MO}_{\rm 4}^{{\rm 5 ‐ }} \to ({\rm RE}_{\rm 3} {\rm M}_{\rm 5} {\rm O}_{{\rm 12}})_{{\rm solid}}$$\end{document}RE rare earth elements, Y;M Al,

ISSN:0232-1300    

DOI:10.1002/crat.2170210604

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170210605

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY