[en] A wide variety of suggested crystallo-chemical formulas is typical of minerals of the phosphuranylite group. Uranyl phosphate formula for phosphuranylite are suggested containing an extra cation ((UO₂)₃(PO₄)₂)x6H₂O and containing a calcium cation. The ratio Ca:(UO₂):PO₄ in the unit of the formula varies, according to the data of various authors, within the limits 0,5:3:2; 1:3:2; 1:4:2. The authors of the article tried to resolve the crystal structure of the mineral according to its monocrystal formation. The empirical chemical formula for phosphuranylite was used: Ca((UO₂)₃(PO₄)₂(OH)₂)x6H₂O. The calculations made by the authors made it possible to find the co-ordinates of the atoms: 8 Ca, 24 U, 16 P, 112 O, 16 OH, and 48 H₂O. The calculations showed that the basic structural unit is a uranyl phosphate layer that is very similar to dumontite. The position of the layers relative to each other can be different, as a result of which the layers form the rhombic structure of phosphuranylite and the monoclinic structure of dumontite. The layer itself may undergo certain changes; this is confirmed by the discovery of three types of uranyl polyhedron is phosphuranylite and two in dumontite. The changes of the U polyhedron and the interatomic distances may be the result of the substitution of OH ions for O; variations in the OH:O ratio may result in a change of the content of the interlayer cation. The (UO₂):(PO₂) ratios must be stable, judging by the structures of phosphuranylite and dumontite. (V.Ya.)

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[en] Paragenetic interactions of coffjnite and pitchblende have been studied by means of modern electron microscopy with microdiffraction diagnostics of minerals. The typemorphous value of these uranium minerals for the characteristic of the formation conditions of parageneses including them. Interrelations of minerals during the paragenesis formation are described using young formations, arizing in the subzone of cementation of linear oxidation zone of hydrothermal ore bodjes, as an example. Signs of simultaneous growth of spheruljtes of pitchblende and incrustate agregate of coffinite crystals in the limits of zone veins of uranium mjnerals as well as coffinite deposition following pitchblende studied on the basis of metasomatic extracts which are not subjected to further hydrothermal alterations. Coformation of coffinite and pitchblende characterises relatively reductive conditions. It is supposed that one of the reasons of spherulite structure of pitchblendes is the distortjon of forms of defect structure crystals made them up already at the stage of their generation and crystal growth

[en] Uranyl phosphate is easily synthesized by adding a 0.36M solution of phosphorous acid of 60degC to a 0.5M solution of uranyle nitrate. The precipitate at pH 0.87-1.10 contains two morphologically different phases - one in the form of quadratic disks (''heavy'' phase) - the other in form of needle-crystals of size up to 0.1 mm (''light'' phase). X-ray analysis determined the ''heavy'' phase as meta-autunite, - the ''light'' phase as uranyl phosphate of composition (UO₂):(PO₄)=3:2. Uranyl phosphate is straw-coloured, its specific weight is 3.45; the luminescence is similar to that of autunite; the refraction index is Nsub(g)=Nsub(m)=1.581; pr=1.570 with a slight pleochroism from light yellow to white; the interference colours are week; the extinction is direct. The chemical analysis of two independently obtained samples of uranyl phosphate was carried out. It led to the crystallo-chemical formula (UO₂)₃(PO₄)₂ x 4,8H₂O. The symmetry and the parameters of the elementary cell of the phosphate are determined: it is a rhombic cell with a=13.11+-0.01A, b=6.98+-0.01A, c=16.91+-0.03A and Z=3. The x-ray density is rho=3.53. The DTA curve shows a higher temperature at the beginning of the dehydration: nearly 120deg compared with the first endoeffect of N-metaautunite which occurs at 50deg. The i.r. spectrum gives a lower symmetry than for N-meta-autunite. The water in the uranyl phosphate is strongly orientated and coupled to the structure. Dumontite which has a ratio (UO₂):(PO₄)=3:2 is found to have a analogous chemical composition to the uranyl phosphate. The parameters b and c are similar in both compounds. The formation of phosphate and the transformation into N-meta-autunite can take place even under natural coditions. The phosphoric analogue of troegerite has the same (UO₂)/(PO₄) ratio but differs in the water content. The structural relations of the two compounds are still unknown

[en] The electron-vibrational luminescence spectra of 15 uranium minerals and 4 minerals containing uranium impurities at 77 and 298 K have been determined. Standard spectra of uranyl minerals make it possible to quickly diagnose. Luminescence spectra of nonuranium minerals make it possible to recognize the basic forms in which uranium enters host minerals: aqua-complexes of uranyl in silica minerals and finely dispersed phases of uranium minerals (ursilites) in calcites. With decreasing chemical-bond multiplicity in uranyl as a result the frequency of symmetric vibration decreases and the colour of luminescence shifts from blue-green to the red-orange part of the spectrum as the anion component of the uranyl minerals changes

[en] Most promising methods of mineralogic analysis of uranium and uranium-containing minerals, ores and rocks are considered. They include X-ray diffraction, electron microscopy and fluorescence spectroscopy methods. Principle physical basis and capabilities of each method are described; examples of its practical application are presented. Comparative characteristic of method for mineralogic analysis of radioactive ores and their reprocessing products is given. Attention is paid to the equipment and various devices for analysis

[en] The book is a manual of most perspective methods of mineralogical analysis of uranium ores and products of their processing, application of which permits to solve problems, which cannot be solved by standard methods. Efficiency of such modern methods as radiography, luminescence spectroscopy and electron microscopy when studying radioactive ores is due to the high degree of uranium scattering in rocks and by dispersity or metamictness of minerals formed by this element

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[en] Uranyl silicate of the viksite group with the formula (Ksub(11)Nasub(0.5)Casub(0.2))(UOsub(2))sub(2)(Sisub(2)Osub(5))sub(3).4-5.8Hsub(2)O has been found for the first time in the USSR in a milybdenum-uranium deposit. The mineral differs from uranyl silicates of the uranophane and the kasolite group in having a high stability of its crystalline structure and a wide cation isomorphism exhibiting no changes in the crystalline structure