Phosphates uranium

Sohd uranium—phosphate complexes have been reported for the IV and VI oxidation states, as well as for compounds containing mixed oxidation states of U(IV) and U(VI). Only a few sohd state stmctures of U(IV) phosphates have been reported, including the metaphosphate U(P03)4, the pyrophosphate U(P202), and the orthophosphate, CaU(PO4)2. The crystal stmcture of orthorhombic CaU(POis similar to anhydrite (194). Compounds of the general formula MU2(PO4)3 have been reported for M = Li, Na, and K, but could not be obtained with the larger Rb and Cs ions (195). In the sohd state, uranium(IV) forms the triclinic metaphosphate, U(P03)4. Each uranium atom is eight-coordinate with square antiprismatic UOg units bridged by... 

Urano-hydroxyd, n. uranous hydroxide, ura-nium(IV) hydroxide, -reihe, /. uranous series, -salz, n. uranous salt, -uranat, n. uranous uranate, uranium(IV,VI) oxide, UaOa. -verbindung, /. uranous compound, Uran-oxyd, n. uranium oxide, specif, uranic oxide, uranium(VI) oxide, UOa. -ozydhydrat, n. uranium hydroxide, -oxydoxydul, n. = Uranoxyduloxyd. -oxydrot, n. uranium oxide red- -oxydul, n. uranous oxide, ura-nium(IV) oxide, UO2. -oxyduloxyd, n. uranoso-uranic oxide, uranium (I V,VT) oxide, UaOa. -oxydulsalz, n. uranous salt, uranium-(IV) salt, -pechblende, /., -pecherz, n. pitchblende, -phosphat, n, uranium phosphate. -rot, n. uranium red. -salz, n. uranium salt. 

Uranium phosphates, 25 432-434 Uranium-phosphine coordination complexes, 25 436 Uranium pickling, 9 788 Uranium-plutonium fuels, 19 668... 

All acid uranium phosphate, UH2(P04)2 or UO2.P2O5.H2O, is obtained as a gelatinous 23recipitate when ordinarj " sodium phosphate, or excess of sodium metaphosphate, is added to a solution of uranous chloride. It may be obtained in the crystalline form as UH2(P04)2.oH20. Aloy also describes a uranous chlorophosjihate of composition UH2(P04)2.UCl4 (see p. 295). 

In the solid state, the major classes actinide(IV) phosphate are orthophosphates, hydrogenpho-sphates, pyrophosphates, metaphosphates, and polyphosphates. In addition there are numerous ternary compounds, mixed valent uranium phosphates, halophosphates, organophos-phates, and most recently, open framework and templated phases. 

Figure 52 Coordination environment (a) about uranyl and within and (b) between uranyl phosphate layers in the first organically templated open-framework uranium phosphate, [Et2NH2]2[(U02)5(P04)4] (Danis,...

The structures of ulrichite, Cu[Ca(H20)2(U02)(P04)2](H20)2, and of the mixed-valence synthetic compound [U (U02)(P04)] also exhibit substitution for uranyl in the uranophane sheet-anion topology (Fig. 46). In ulrichite, CaOs polyhedra alternate with uranyl pentagonal bipyramids, and the sheets are connected by Jahn-Teller-distorted Cu-centered octahedra [177]. In the structure of [U" (U02)(P04)], both and are in sevenfold coordination to form pentagonal bipyramids. Dimers of polyhedra alternate with dimers of uranyl pentagonal bipyramids along the uranium phosphate chains that make up the sheet (Fig. 46). The polyhedra also share vertices with tetrahedra of adjacent sheets to form a framework structure [178]. 

The NZP structure t) e of the high temperature modifications of actinide phosphates AM2(P04)3 has been confirmed by the Rietveld refinement of the uranium phosphate KU2(P04)3 [50]. The test sample was obtained by means of heating of the monoclinic phosphate of similar stoichiometry at 1350 °C in Ar atmosphere. As shown in Figs. 2 and 3, the UOn polyhedra of monoclinic and rhombohedral stmctures of KU2(P04)3 are different UO9 and UOe, respectively. 

Many minerals have been shown to form as the result of direct or indirect biological processes (e.g., see Ehrlich 1999). Organismal production of a vast diversity of other phases, including phosphates (bones and teeth), actinide minerals (including uraninite and uranium phosphates), elemental sulfur, etc. are well known. In addition to processes described above, high concentrations of nanoparticles are generated in proximity to cells as the result of changes in solution saturation state due to uptake or release of protons or... 

National Academy of Sciences. Redistribution qf Assessory Elements in Mining and Mineral Processing. Pan II. Uranium. Phosphate, and Alumina. Washingtim. DC, 1979. pp. SS and 71. 

All uranium ori contain radium and consequently may serve as a source nf radium. Torhemite, a by dinted cupper uranium phosphate, and antnnite, a hydrated calcium uranium phosphate, are found in Portugal ami Australia, from which considerable radium has been extracted. Then am apparently extensive deposits of low grade torbnrnite and niitunile in New Mexico. 

ViiCHfiVafice determination of phosphates in urine.—A process for determining the quantity of phosphates in urine is based upon the formation of the insoluble uranium phosphate, and upon the production of a... 

The hexavalent-uranium phosphate minerals (Table 14) are important and widespread uranyl-oxysalt minerals. Their structures and behavior are dominated by the crystal chemistry of the (U 02) uranyl group they have been described in detail by Burns (1999) and will not be considered any further here. 

Birch WD, Mumme WG, Segnit ER (1988) Ulrichite A new copper calcium uranium phosphate from Lake Boga, Victoria, Australia. Aust Mineral 3 125-131... 

A large variety of secondary uranium minerals are known, many are brilliantly colored and fluorescent. The commonest are gummite (a general term like limonite for mixtures of various secondary hydrated uranium oxides with impurities) hydrated uranium phosphates of the phosphuranylite type, including autunite (with calcium), saleeite (magnesium), and torbernite (with copper) and hydrated uranium silicates such as cof-finite, uranophane (with calcium), and sklodowskite (magnesium). 

Another uranium phosphate mineral, lermontovite, has been described by Soboleva and Pudovkina. This mineral occurs as botryoidal aggregates of radial fibrous needles. The formula is apparently U3(P04)4-6H20 with some substitution of Ca and RE for the U. The material is poorly characterized. It is associated with molybdenum sulphate, marcasite, hydrous silicates and thallium ochre . This phase requires more careful characterization. 

Ore-bearing zones have much coaly material and carbonized wood. The ore consists of uraninite and coffinite, which occur as black coatings on grains and as interstitial fillings. They are accompanied by Se, Mo and As enrichment. Oxidized zones (above the water-table) contain uranium phosphates, silicates and hydrous oxides. It is estimated that the Gas Hills district will ultimately produce about 75 000 ton UsOg. 

Kryukova, A.I., Korshunov, lA., Bmnaeva, A.A. et al. (1981) Effect of the physicochemical conditions on the composition and properties of uranium phosphates precipitated from a chloride melt Sov. Radiochem, 23(1), 106-109. 

Mokry, L. M., Dean, N. S., and Carrano, C. J. 1996. Synthesis and structure of a discrete hexanuclear uranium-phosphate complex. Angew. Chem. Int. Ed. Engl. 

Uranium -phosphate. Neither hexavalent nor tetravalent uranium phosphate is sufficiently soluble in water to be of reactor interest, but both UO2 and UO3 are quite soluble in moderately strong phosphoric acid. These solutions have been the subject of considerable study at the Los Alamos Scientific Laboratory [15]. The solubility of UO3 in phosphoric acid is illustrated by Fig. 3-12 [16]. Although the solubilities of uranyl... 

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