12058-37-6

Basic information

• Product Name: nitridouranium
• CAS NO: 12058-37-6
• Molecular Formula: NU
• Molecular Weight: 252.0356
• Mol File: 12058-37-6.mol

Chemical Properties

• CAS DataBase Reference: nitridouranium(CAS DataBase Reference)
• NIST Chemistry Reference: nitridouranium(12058-37-6)
• EPA Substance Registry System: nitridouranium(12058-37-6)

Safety Data

• Hazardous Substances Data: 12058-37-6(Hazardous Substances Data)

Upstream product

• 7727-37-9 nitrogen 
• 80937-33-3 oxygen 
• 7664-41-7 ammonia 
• 10049-14-6 uranium(IV) tetrafluoride 
• 10026-08-1 thorium tetrachloride 
• 10026-10-5 uranium(IV) chloride 
• 13775-06-9 uranium(III) trifluoride 

Relevant articles and documents

Formation of a nitrogen-rich α-U2N3+x phase by the reaction of uranium with a stream of ammonia

The reactions U + NH3(stream) and U + N2(stream) were performed in the temperature range from 400 to 800°C. The results show that the use of a stream of NH3 leads to the formation of nitrogen-rich uranium sesquinitrides, which cannot be obtained by the reactions of uranium with N2 under normal pressures, suggesting that a stream of NH3 possesses higher nitrogen activity compared with N3 at 1 atm. The experimental results were analyzed on the basis of thermodynamic considerations. It was found that enormously high nitrogen pressures would be required to obtain nitrogen-rich uranium sesquinitride as prepared by the reaction of uranium with a stream of NH3, if one tried to prepare this material by the reaction of uranium with N2.

The enthalpies of formation of uranium mononitride and α- and β-uranium sesquinitride by fluorine bomb calorimetry

The energies of combustion in fluorine of uranium mononitride and α- and β-uranium sesquinitride were measured in a bomb calorimeter.The derived standard enthalpies of formation, ΔH0f(UNx, c, 298.15 K), are -(290.3 +/- 2.2), -(391.5 +/- 2.3), -(382.2 +/- 2.3), and -(362.9 +/- 2.3) kJ mol-1 for UN0.997, α-UN1.674, α-UN1.606, and β-UN1.466, respectively.

Electrochemical behaviors of PuN and (U, Pu)N in LiCl-KCl eutectic melts

Electrochemical behaviors of PuN and (U, Pu)N in the LiCl-KCl eutectic melts at 773 K were investigated by cyclic voltammetry. The electrochemical dissolution of PuN and (U, Pu)N began nearly at -0.90±0.05 and -0.95±0.05 V (vs. Ag+/Ag), respectively. The rest potentials of PuN and (U, Pu)N were observed at about 0.15 V more negative potential than that of UN, in the present experimental condition. The observed rest potentials of (U, Pu)N depended on the equilibrium potential of the Pu3+/PuN. In the cyclic voltammogram measured by use of (U, Pu)N as the working electrode, a steep rise of the positive current was observed at potentials more positive than -0.45 V in analogy with the cyclic voltammogram measured by use of UN as the working electrode. These indicate that UN and PuN in (U, Pu)N would be dissolved independently irrespective of forming the solid solution.

Lithium-Uranium-Nitrides: LiUN2 and Li2UN2

The synthesis of LiUN2 started with a mixture of Li 3N with UH3 reacted under N2 at 900°C within 3 d. The compound crystallizes (X-ray and neutron diffraction powder data) tetragonal in the space group I41/amd with Z = 4 and a = 4. 3965 (2) A?, c = 11.059 (4) A?. The Structure is related to the anatase type (TiO2 ? UN2) with filled up octahedral sites by Li. The compound is a paramagnetic semiconductor. Reactions of mixtures of Li3N and UH3 (3:1) at 600°C result as the main product in a Li2UN2 just known for a long time. In contrary to the earlier investigations our product does not crystallize in the space group P3? with Z = 3 but in P3? m1 with Z = 1. Mixtures in a molar ratio of 5:1 reacted at 500°C give a product that crystallizes cubic with a = 4.890 (1) A?. Its lattice constant resembles that of UN. Reactions carried out with high molar ratios of educts from 5:1 to 10:1 and temperatures ≥ 800°C give Guinier diagrams indicating a further phase in the system Li/U/N with a somewhat complicated structure as to the number of X-ray lines.

Preparation and photoelectron spectroscopy study of UNx thin films

Thin films of UN and U2N3 were prepared by reactive DC sputtering of U in N2-containing atmosphere. The composition of the films was modified by varying the partial pressure of N2. 4f-Core-level photoelectron spectra as well as valence-band spectra obtained with HeII and HeI photoexcitation confirm the itinerant character of the 5f-electronic states in UN, showing a high density of states at the Fermi energy. The 4f peaks in U2N3 are shifted towards higher binding energy and are symmetric, indicating a low density of states at the Fermi level. Valence-band spectra show indeed a maximum of 5f emission at 0.8 eV below the Fermi level, but some 5f intensity at the Fermi level is preserved, contradicting full 5f localization.

Reaction sequence and kinetics of uranium nitride decomposition

The reaction mechanism and kinetics of the thermal decomposition of uranium dinitride/uranium sesquinitride to uranium mononitride under inert atmosphere at elevated temperature were studied. An increase in the lattice parameter of the UN2/α-U

Photoemission study of UNxOy and UCxO y in thin films

Thin films of UNxOy and UCxOy have been prepared by reactive sputtering of U in an Ar atmosphere containing O2 and N2 admixtures, and of U and C in an Ar/O 2 atmosphere. The C content of the films was controlled by the carbon target voltage, and N and O contents were adjusted by the respective partial pressures of O2 and N2. Surface composition and electronic structure were studied by X-ray and ultra-violet photoemission spectroscopies (XPS and UPS, respectively). In most cases, the films were mixtures of the binary carbides (UC and UC2) or nitrides (UN and U2N 3), UO2 and U metal. The high reactivity of oxygen, compared to C and N2 was demonstrated. At low oxygen pressure, indications for formation of ternary uranium oxycarbides (UCxO 1-x) or oxynitrides (UNxO1-x) were obtained. These ternaries are solid solutions of UO and UC or UN (compounds containing a second constituent which fits into and is distributed in the lattice of the host compound). The metallic nature of uranium oxycarbides and oxynitrides (at low oxygen content) and the itinerant character of their 5f electrons were demonstrated.

Preparation of UH3 by the reaction of U with NH3 or with a mixture of H2 and N2

To examine how a high nitrogen activity and high hydrogen activity can be obtained by keeping the extent of dissociation of NH3 below its dissociation equilibrium, reactions of U with static NH3 were carried out at 250 °C. The formation of N-rich U2N3+x, and that of UH3 are discussed from a thermodynamic point of view. The experimental results suggest, however, that the formation of UH3 must be ascribed to a much lower activation energy for its formation.