Thorium compounds with non-metals: Electronic structure, chemical bond, and physicochemical properties

Shein, I. R.; Ivanovskiĭ, A. L.

doi:10.1007/s10947-008-0134-0

Cited by 28 publications

(20 citation statements)

References 76 publications

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“…This is consistent with experimental findings that suggest the existence of two stable alloys of thorium and nitrogen, namely ThN and Th 3 N 4 . [45] The bulk and shear moduli increases from ThN 2 to UN 2 , then subsequently decreases to PuN 2 . The calculated bulk modulus, shear modulus and Debye temperature with and without the U parameter for PaN 2 and UN 2 are consistent for the AFM and the FM phases as shown in Table 2.…”

Section: Elastic Propertiesmentioning

confidence: 95%

GGA+U studies of the early actinide mononitrides and dinitrides

Obodo

Chetty

2013

Journal of Nuclear Materials

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Abstract. We present a detailed comparative study of the electronic and mechanical properties of the early actinide mononitrides and dinitrides within the framework of the Perdew-Burke-Ernzerhof generalized gradient approximation (GGA [PBE]) and GGA + U implementations of density functional theory with the inclusion of spin-orbit coupling. The dependence of selected observables of these materials on the effective U-parameter is investigated in detail. The properties include the lattice constant, bulk modulus, charge density distribution, hybridization of the atomic orbitals, energy of formation and the lattice dynamics. The inclusion of the Hubbard U parameter results in a proper description of the 5f electrons, and is subsequently used in the determination of the structural and electronic properties of these compounds. The mononitrides and dinitrides of the early actinides are metallic except for UN 2 , which is a semiconductor. These actinide nitrides are non-magnetic with the exception of UN, NpN, PuN, NpN 2 and PuN 2 that are magnetic systems with orbital-dependent magnetic moments oriented in the z-axis. We observed that ThN 2 is elastically unstable to isotropic pressure. We discovered that UN 2 is thermodynamically unstable, but may be stabilized by N vacancy formation.

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Section: Elastic Propertiesmentioning

confidence: 95%

GGA+U studies of the early actinide mononitrides and dinitrides

Obodo

Chetty

2013

Journal of Nuclear Materials

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“…[19] and the theoretical FLAPW-GGA results in Ref. [26] are also presented. As can be seen from Table III, our calculated C 12 and C 44 are in agreement with the FLAPW-GGA results, while C 11 =334.8 GPa is smaller than the corresponding data 396.6 GPa.…”

mentioning

confidence: 99%

Electronic structures, mechanical and thermodynamic properties of ThN from first-principles calculations

Wang

et al. 2011

Journal of Nuclear Materials

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Lattice parameter, electronic structure, mechanical and thermodynamic properties of ThN are systematically studied using the projector-augmented-wave method and the generalized gradient approximation based on the density functional theory. The calculated electronic structure indicates the important contributions of Th 6d and 5f states to the Fermi-level electron occupation. Through Bader analysis it is found that the effective valencies in ThN can be represented as Th +1.82 N −1.82 .Elastic constant calculations shows that ThN is mechanically stable and elastically anisotropic.Furthermore, the melting curve of ThN is presented up to 120 GPa. Based on the phonon dispersion data, our calculated specific heat capacities including both lattice and conduction-electron contributions agree well with experimental results in a wide range of temperature.

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“…This pattern also shows two variations of ThC 2 which are monoclinic and cubic in equilibrium with Th 2 NiC 2 . The Th-C binary system has two basic phases, mono (ThC) and dicarbide (ThC 2 ) [14]. The dicarbide exists as three polymorphic modifications called α, β and γ .…”

Section: Methodsmentioning

confidence: 99%

Th₂NiC₂: a low density of states superconductor

Machado¹,

Grant²,

Fisk³

2012

Supercond. Sci. Technol.

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The metallic carbides exhibit many novel prototypes of crystalline structure. Among these compounds Th 2 NiC 2 was reported in 1991 as a new carbide which crystallizes in the U 2 IrC 2 prototype structure. In this work we report a reinvestigation of the synthesis of this compound. We find that Th 2 NiC 2 is a new superconductor. Our results suggest that this phase is stable only at high temperatures in the system Th-Ni-C. The substitution of Th by Sc stabilizes the phase and improves the superconducting properties. The highest superconducting critical temperature occurs at 11.2 K with nominal composition Th 1.8 Sc 0.2 NiC 2 . The electronic coefficient determined by specific heat measurements is close to zero. This unusual result can be explained by covalent bonding in the compound.

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Thorium compounds with non-metals: Electronic structure, chemical bond, and physicochemical properties

Cited by 28 publications

References 76 publications

GGA+U studies of the early actinide mononitrides and dinitrides

GGA+U studies of the early actinide mononitrides and dinitrides

Electronic structures, mechanical and thermodynamic properties of ThN from first-principles calculations

Th₂NiC₂: a low density of states superconductor

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Thorium compounds with non-metals: Electronic structure, chemical bond, and physicochemical properties

Cited by 28 publications

References 76 publications

GGA+U studies of the early actinide mononitrides and dinitrides

GGA+U studies of the early actinide mononitrides and dinitrides

Electronic structures, mechanical and thermodynamic properties of ThN from first-principles calculations

Th2NiC2: a low density of states superconductor

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Product

Resources

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Th₂NiC₂: a low density of states superconductor