Results for “NaCuTe”

DOE OSTI2020

Materials Data on NaCuTe by Materials Project

NaCuTe is Matlockite structured and crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Na1+ is bonded to five equivalent Te2- atoms to form distorted NaTe5 trigonal bipyramids that share corners with twelve equivalent CuTe4 tetrahedra, corners with four equivalent NaTe5 trigonal bipyramids, edges with four equivalent CuTe4 tetrahedra, and edges with eight equivalent NaTe5 trigonal bipyramids. There are four shorter (3.19 Å) and one longer (3.22 Å) Na–Te bond lengths. Cu1+ is bonded to four equivalent Te2- atoms to form CuTe4 tetrahedra that share corners with four equivalent CuTe4 tetrahedra, corners with twelve equivalent NaTe5 trigonal bipyramids, edges with four equivalent CuTe4 tetrahedra, and edges with four equivalent NaTe5 trigonal bipyramids. All Cu–Te bond lengths are 2.71 Å. Te2- is bonded in a 9-coordinate geometry to five equivalent Na1+ and four equivalent Cu1+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Transuranium Sulfide via the Boron Chalcogen Mixture Method and Reversible Water Uptake in the NaCu T S 3 Family

The behavior of 5f electrons in soft ligand environments makes actinides, and especially transuranium chalcogenides, an intriguing class of materials for fundamental studies. Due to the affinity of actinides for oxygen, however, it is a challenge to synthesize actinide chalcogenides using non-metallic reagents. Using the Boron Chalcogen Mixture (BCM) method, we achieved the synthesis of the transuranium sulfide NaCuNpS 3 starting from the oxide reagent, NpO 2 . Via the same synthetic route, the isostructural composition of NaCuUS 3 was synthesized and the material contrasted with NaCuNpS 3 . Single crystals of the U-analog, NaCuUS 3 , were found to undergo an unexpected reversible hydration process to form NaCuUS 3 ·xH 2 O (x ≈ 1.5). Here, a large combination of techniques was used to fully characterize the structure, hydration process, and electronic structures, specifically a combination of single crystal, powder, high temperature powder X-ray diffraction, extended X-ray ab-sorption fine structure, infrared, and inductively coupled plasma spectroscopies, thermogravimetric analysis, and density functional theory calculations. The outcome of these analyses enabled us to determine the composition of NaCuUS 3 ·xH 2 O and obtain a structural model that demonstrated the retention of the local structure within the [CuUS 3 ] – layers throughout the hydration-dehydration process. Band structure, density of states, and Bader charge calculations for NaCuUS 3 , NaCu-US 3 ·xH 2 O, and NaCuNpS 3 along with X-ray absorption near edge structure, UV-vis-NIR and work function measurements on ACuUS 3 (A = Na, K, and Rb) and NaCuUS 3 ·xH 2 O samples were carried out to demonstrate that electronic properties arise from the [CuTS 3 ] – layers and show surprisingly little dependence on the interlayer distance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗