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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,711 records · Page 95
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

AREVA NP MR Cladding benefits for proposed US NRC RIA and LOCA requirements

M5 is the reference alloy of AREVA NP for PWR cladding applications. It is a zirconium-based alloy containing 1% niobium, no tin, and well-controlled oxygen, iron, and sulfur contents. It has a fully recrystallized microstructure. The absence of tin in M5 results in a very low corrosion rate and hydrogen pick-up during normal operation, even at high burn-up and in high duty irradiation conditions. Due to this low hydrogen pick-up under irradiation (typically less than 100 ppm, End of Life), M5 retains a very good strength and an exceptional residual ductility during and after the accident. This allows utilities implementing M5 to simplify the safety analysis and to demonstrate significant margins regarding fuel related criteria. Simplified methods are easier for plants to implement and maintain for future plant operations and core design management. This paper specifically presents 3 examples on the safety improvement brought by M5 cladding. First, during a reactivity-induced accident (RIA), the properties of M5 are such that bounding analyses for future cycles are significantly simplified, in particular by demonstrating that fuel dispersal will not occur. The major aspects of the AREVA NP RIA methodology are presented. A second focus is made on the low hydrogen embrittlement of M5 and on its high ductility after quenching during a loss-of-coolant accident (LOCA). In a third part, the breakaway oxidation testing program currently under development in Paimboeuf (France) is described, including details about the testing devices and qualification. The tests have demonstrated that M5 cladding does not have breakaway at least up to 5000 s oxidation duration at 1000 C. degrees, which is much higher than the LOCA duration.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2013

Preparation, characterization and gas sensitivity of polypyrrole/γ-Fe{sub 2}O{sub 3} hybrid materials

Graphical abstract: - Highlights: • PPy/γ-Fe{sub 2}O{sub 3} hybrid materials were prepared by sol–gel polymerization in situ. • Different reactant molar ratios resulted in different microstructures of γ-Fe{sub 2}O{sub 3} and molecular weights of PPy. • PPy/γ-Fe{sub 2}O{sub 3} hybrids had selectivity for NH{sub 3} gases at low temperatures (<100 °C). • The sensing mechanism was suggested to be related to the existence of p–n heterojunctions in the PPy/γ-Fe{sub 2}O{sub 3} hybrid material. - Abstract: Polypyrrole (PPy)/γ-Fe{sub 2}O{sub 3} hybrid materials were prepared by sol–gel polymerization in situ and characterized by Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), thermogravimetric and differential thermal analysis (TG–DTA) and high-resolution transmission electron microscope (HRTEM). The gas sensitivities in CO, H{sub 2}, NH{sub 3}, ethanol or acetone atmospheres were determined at 30 °C, 60 °C and 90 °C. FT-IR and XRD patterns suggest that ferric oxide in the hybrids was γ-Fe{sub 2}O{sub 3}, with a diameter of approximately 5 nm. TG–DTA and HRTEM analyses showed that different reactant molar ratios of pyrrole monomer: Fe(NO{sub 3}){sub 3}·9H{sub 2}O resulted in different microstructures of γ-Fe{sub 2}O{sub 3} and molecular weights of PPy. An increased amount of Fe(NO{sub 3}){sub 3}·9H{sub 2}O increased the degree of uniformity of the molecular weight of PPy and resulted in a change of γ-Fe{sub 2}O{sub 3} microstructure from granular to stick particles. The results of gas sensitivities showed that the PPy/γ-Fe{sub 2}O{sub 3} hybrids exhibited high sensitivity to NH{sub 3} at mild operating temperature (<100 °C). Furthermore, the sensing mechanism was also discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Evolution of carbide precipitates in Haynes® 282 superalloy processed by wire arc additive manufacturing

Precipitation hardening regulated with heat treatments is a critical technique for tuning the mechanical properties of Ni-based superalloys fabricated with additive manufacturing, where mechanical deformation is no longer viable for microstructural refinement. As one of the key precipitates, carbides prevail in the additively manufactured alloys, whose precipitation kinetics remain largely vague. This work studies the influence of heat treatments on the evolution of MC- and M 23 C 6 -type carbides within a Haynes® 282 superalloy prepared by wire arc additive manufacturing (WAAM). SEM-EDS analysis was performed to identify the evolution pathways of the carbides, and TEM and XRD characterizations were carried out to track the crystallographic features. The MC-type carbides are originally present in the as-printed alloy, which distribute uniformly across the whole material and remain largely unchanged in size during the heat treatments. By contrast, the incipiently non-existent M 23 C 6 -type carbides precipitate during an aging treatment at 1010 °C, which majorly extend along the grain boundaries as kinetically feasible sites. Further experimental and computational analysis confirms the enhancing effect of the M 23 C 6 -type carbides on the Vickers hardness. For the first time, this work revealed the evolution pathways of carbides within a Haynes® 282 superalloy prepared by WAAM, providing critical information for tunning the microstructure and mechanical properties. Finally, the carbide evolution kinetics established in this work can be potentially extended to other alloys prepared with WAAM, providing critical information to prevent mechanical failures associated with carbide coarsening.

36 MATERIALS SCIENCE↗
DOE OSTI2010

Product gas evolution above planar microstructured model catalysts--A combined scanning mass spectrometry, Monte Carlo, and Computational Fluid Dynamics study

The transport and distribution of reaction products above catalytically active Pt microstructures was studied by spatially resolved scanning mass spectrometry (SMS) in combination with Monte Carlo simulation and fluid dynamics calculations, using the oxidation of CO as test reaction. The spatial gas distribution above the Pt fields was measured via a thin quartz capillary connected to a mass spectrometer. Measurements were performed in two different pressure regimes, being characteristic for ballistic mass transfer and diffusion involving multiple collisions for the motion of CO{sub 2} product molecules between the sample and the capillary tip, and using differently sized and shaped Pt microstructures. The tip height dependent lateral resolution of the SMS measurements as well as contributions from shadowing effects, due to the mass transport limitations between capillary tip and sample surface at close separations, were evaluated and analyzed. The data allow to define measurement and reaction conditions where effects induced by the capillary tip can be neglected (''minimal invasive measurements'') and provide a basis for the evaluation of catalyst activities on microstructured model systems, e.g., for catalyst screening or studies of transport effects.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Chemical diffusion: Another factor affecting the magnetoresistance ratio in Ta/CoFeB/MgO/CoFeB/Ta magnetic tunnel junction

This letter investigates the microstructure and mean inner potential (MIP) profile of Ta/CoFeB/MgO/CoFeB/Ta magnetic tunnel junctions (MTJs) by high resolution transmission electron microscopy (HRTEM) and electron holography, respectively. The inconspicuous crystallization of MgO barrier is confirmed by HRTEM in the post-annealed sample at 250 Degree-Sign C. An obvious MIP difference is displayed in the Ta layers between the top and bottom of the MTJ, and elemental content difference of them is confirmed by energy dispersive spectroscopy. These results imply that the chemical diffusion can also give rise to a lower tunnel magnetoresistance ratio besides the inconspicuous crystallization of MgO barrier.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Development and setting of a new system for advanced rheocast components

This paper presents an overview of alternative methods of production of enhanced performance Al-based alloys components for critical areas. In particular, a new rheocasting system, suitable for the manufacturing of high performance industrial components has been considered. The aforementioned method allows obtaining component quickly and results a more convenient process, from economical point of view than other innovative processes. Two series of components have been produced with A356 and A357 alloys, then have been heat treated using T5 and T6 treatments. On polished transverse sections of samples the microstructure of the alloy has been observed. Their soundness has been previously certified by non destructive tests. Samples for tensile and three point bending tests have been machined directly from the produced components. On the fractured samples, fracture surface analysis has been performed in order to analyze and evaluate the influence of the process and of the alloy on the fracture behaviour.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Three-dimensional plastic response in polycrystalline copper via near-field high-energy X-ray diffraction microscopy

The evolution of the crystallographic orientation field in a polycrystalline sample of copper is mapped in three dimensions as tensile strain is applied. Here, using forward-modeling analysis of high-energy X-ray diffraction microscopy data collected at the Advanced Photon Source, the ability to track intragranular orientation variations is demonstrated on an ~2 µm length scale with ~0.1° orientation precision. Lattice rotations within grains are tracked between states with ~1° precision. Detailed analysis is presented for a sample cross section before and after ~6% strain. The voxel-based (0.625 µm triangular mesh) reconstructed structure is used to calculate kernel-averaged misorientation maps, which exhibit complex patterns. Simulated scattering from the reconstructed orientation field is shown to reproduce complex scattering patterns generated by the defected microstructure. Spatial variation of a goodness-of-fit or confidence metric associated with the optimized orientation field indicates regions of relatively high or low orientational disorder. An alignment procedure is used to match sample cross sections in the different strain states. The data and analysis methods point toward the ability to perform detailed comparisons between polycrystal plasticity computational model predictions and experimental observations of macroscopic volumes of material.

36 MATERIALS SCIENCE↗
DOE OSTI2010

Quantification of the degree of reaction of fly ash

The quantification of the fly ash (FA) in FA blended cements is an important parameter to understand the effect of the fly ash on the hydration of OPC and on the microstructural development. The FA reaction in two different blended OPC-FA systems was studied using a selective dissolution technique based on EDTA/NaOH, diluted NaOH solution, the portlandite content and by backscattered electron image analysis. The amount of FA determined by selective dissolution using EDTA/NaOH is found to be associated with a significant possible error as different assumptions lead to large differences in the estimate of FA reacted. In addition, at longer hydration times, the reaction of the FA is underestimated by this method due to the presence of non-dissolved hydrates and MgO rich particles. The dissolution of FA in diluted NaOH solution agreed during the first days well with the dissolution as observed by image analysis. At 28 days and longer, the formation of hydrates in the diluted solutions leads to an underestimation. Image analysis appears to give consistent results and to be most reliable technique studied.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Influence of rolling reduction and annealing on recrystallization and grain structure in Ta-2.5W alloys

The microstructural evolution of wrought Tantalum - 2.5 wt% Tungsten (Ta-2.5W) alloys during thermomechanical processing is critical for optimizing their mechanical reliability in demanding applications such as aerospace, chemical processing, and nuclear technology. Despite the widespread use of Ta-W alloys, a comprehensive understanding of how rolling reduction, annealing temperature, and elemental inhomogeneity interact to determine recrystallization behavior and grain refinement remains incomplete. Here, in this study, we systematically investigate the effects of cold rolling and subsequent annealing on the microstructure of Ta-2.5W, with particular attention to grain orientation, stored energy, and elemental banding. Our results demonstrate that higher rolling reduction rates lower the onset and completion temperatures for recrystallization, resulting in finer and more homogeneous grain structures. Electron backscatter diffraction (EBSD) analysis reveals that grains with a 〈111〉 parallel to the plate normal possess higher stored energy and nucleate recrystallization more readily than grains with a 〈001〉 parallel to the plate normal. Elemental mapping shows that tungsten inhomogeneity leads to localized bands of accelerated recrystallization and hardness variation. These findings provide new insights into the mechanisms of microstructure refinement in Ta-2.5W alloys, offering guidance for tailoring processing routes to achieve superior performance in demanding engineering environments.

Annealing↗
DOE OSTI2011

Durability Prediction of Solid Oxide Fuel Cell Anode Material under Thermo-Mechanical and Fuel Gas Contaminants Effects

Solid Oxide Fuel Cells (SOFCs) operate under harsh environments, which cause deterioration of anode material properties and service life. In addition to electrochemical performance, structural integrity of the SOFC anode is essential for successful long-term operation. The SOFC anode is subjected to stresses at high temperature, thermal/redox cycles, and fuel gas contaminants effects during long-term operation. These mechanisms can alter the anode microstructure and affect its electrochemical and structural properties. In this research, anode material degradation mechanisms are briefly reviewed and an anode material durability model is developed and implemented in finite element analysis. The model takes into account thermo-mechanical and fuel gas contaminants degradation mechanisms for prediction of long-term structural integrity of the SOFC anode. The proposed model is validated experimentally using a NexTech ProbostatTM SOFC button cell test apparatus integrated with a Sagnac optical setup for simultaneously measuring electrochemical performance and in-situ anode surface deformation.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2014

Homogeneous carbon doping of magnesium diboride by high-temperature, high-pressure synthesis

We have used high-pressure, high-temperature synthesis at 1500–1700 °C and 10 MPa to create homogeneously C-substituted MgB{sub 2} from a B{sub 4}C + Mg mixture. X-ray diffraction analysis showed large peak-shifts consistent with a decrease in the a lattice parameter for the B{sub 4}C-derived MgB{sub 2} as compared to an undoped sample (0.033–0.037 Å, depending on the sample). Microstructural investigation showed a three-phase mixture in the B{sub 4}C-derived ingots: MgB{sub 2−x}C{sub x} (with 0.178 < x < 0.195), MgB{sub 2}C{sub 2}, and Mg. The carbon concentration determined from the lattice parameter shift (5.95 at. %) matched well with the calorimetrically derived concentration of 5.3–5.8 at. % C. Furthermore, the carbon content measured by electron probe micro-analysis was shown to be 6.2 ± 1.3 at. %. Finally, we performed bulk specific heat measurements to determine the homogeneity of C-doping in the MgB{sub 2}. The width of the T{sub c} distribution for the C-doped MgB{sub 2} was only 3–6 K with a full-width half maximum (FWHM) of 1.4 K, compared to a width of 2.5 K and a FWHM of 0.65 for an undoped sample. The consistency of these three measurements on a large-grained homogeneous material is unambiguously supportive of C-substitution.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Microstructural, optical and electrical properties of CdS thin films grown by spray pyrolysis technique as a function of substrate temperature

In this research, nanocrystalline cadmium sulfide thin films were produced by the spray pyrolysis technique on glass substrates. The effects of substrate temperature in the range 400–550 °C on the structural, morphological, optical, and electrical properties of the thin films were investigated. The thin films have been characterized by investigating their X-ray diffraction, field emission scanning electron microscope (FE-SEM), and optical absorption (UV–Vis) measurements. X-ray analysis revealed that thin films were a polycrystalline structure with the hexagonal phase in all cases and by increasing in substrate temperature, crystallite size decreases, and dislocation density increases. The FE-SEM images showed that the surface of the thin films is uniform, homogeneous and without cracks. The average sizes of the grains are at the range of 210–235 nm. The obtained values for optical band gap have been in the range of 2.18–2.41 eV, where the value of optical band gap for the thin films decreases by increasing substrate temperature. The Urbach energies of the thin films increase as the substrate temperature is increased. When substrate temperature increased from 400 to 550 °C, electrical resistivity increased from 531 to 2817 Ω cm, carrier concentration decreased from 15.96 × 10{sup 14} to 3.71 × 10{sup 14} cm{sup −3}, Hall mobility decreased from 7.37 to 5.98 cm{sup 2}/V s. Hall effect analysis indicated that the thin films exhibited n-type conductivity.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2011

Enhanced characteristics of Ba{sub 5}SmTi{sub 3}Nb{sub 7}O{sub 30} ferroelectric nanocrystalline ceramic prepared by mechanical activation process: A comparative study

Graphical abstract: In the present work, structural, dielectric, ferroelectric, piezoelectric and pyroelectric properties of tungsten-bronze structured Ba{sub 5}SmTi{sub 3}Nb{sub 7}O{sub 30} ceramics, synthesized by mechanical activation and conventional solid-state reaction processes, have been studied with an objective of comparing the properties of the specimens synthesized by the two processes. The specimen prepared using mechanical activation process exhibits improved structural and electrical properties. Research highlights: {yields} In this report Ba{sub 5}SmTi{sub 3}Nb{sub 7}O{sub 30} compounds have been synthesized. {yields} Synthesis was carried out by mechanical activation and solid-state reaction processes. {yields} The mechanical activation process yields nanocrystalline specimen. {yields} The synthesized specimens were characterized for their electrical properties. {yields} A comparative study reveals that nanocrystalline specimen possesses superior properties. -- Abstract: In the present work, structural, dielectric, ferroelectric, piezoelectric and pyroelectric properties of tungsten-bronze structured Ba{sub 5}SmTi{sub 3}Nb{sub 7}O{sub 30} ceramics, synthesized by mechanical activation and conventional solid-state reaction processes, have been studied with an objective of comparing the properties of the specimens synthesized by the two processes. X-ray diffraction analysis shows the formation of the compound in an orthorhombic structure by both the processes. Scanning electron microscopy reveals the formation of a fine granular microstructure in the specimen synthesized by mechanical activation process compared to the specimen synthesized by conventional solid-state method. The specimen prepared using mechanical activation process exhibits improved electrical properties with higher dielectric constant, lower dielectric loss and higher resistivity. The effective remanent polarization (P{sup -bar{sub r}}) value, d{sub 33} value and pyroelectric coefficients are also observed to be higher in the sample synthesized by the mechanical activation process.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Nanoscale Phase Separation and Large Refrigerant Capacity in Magnetocaloric Material LaFe 11.5 Si 1.5

Here, ferromagnetic transitions, the magnetocaloric effect, and the atomic-scale microstructure in an annealed bulk material of LaFe 11.5 Si 1.5 were investigated using magnetic measurements, Mössbauer spectroscopy, high-resolution X-ray diffraction analysis, and high-resolution transmission electron microscopy. The results provide evidence of the coexistence of two ferromagnetic phases with different Curie temperatures. The phase with a Curie temperature of 216 K corresponds to a Si-rich phase of a NaZn 13 -type structure with a small lattice volume, whereas the phase with a Curie temperature of 185 K corresponds to a Si-poor phase of a NaZn 13 -type structure with a large lattice volume. This phase coexistence is observed on a nanometer scale and it can account for inverse thermal hysteresis of the ferromagnetic transition in the Si-rich phase during warming. Furthermore, the phase coexistence helps the bulk material achieve a refrigeration capacity of 170 J kg -1 due to a combination of the magnetocaloric effect in each phase. It is determined that the magnetocaloric effect in the Si-rich and the Si-poor phase brings about a maximum of the total entropy change of -3.55 and -6.80 and J kg -1 K -1 at respective Curie temperatures, respectively. Fundamentally, the phase coexistence indicates coloring of Si atoms in the lattice of a NaZn 13 -type structure and can be attributed to nanoscale phase separation of a disordered precursor during annealing of the bulk material. The nanoscale phase separation may occur in other magnetocaloric materials, thus allowing for improvement of their refrigeration capacity.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Chaotic behavior of light-assisted physical aging in arsenoselenide glasses

The theory of strange attractors is shown to be adequately applicable for analyzing the kinetics of light-assisted physical aging revealed in structural relaxation of Se-rich As-Se glasses below glass transition. Kinetics of enthalpy losses is used to determine the phase space reconstruction parameters. Observed chaotic behaviour (involving chaos and fractal consideration such as detrended fluctuation analysis, attractor identification using phase space representation, delay coordinates, mutual information, false nearest neighbours, etc.) reconstructed via the TISEAN program package is treated within a microstructure model describing multistage aging behaviour in arsenoselenide glasses. This simulation testifies that photoexposure acts as an initiating factor only at the beginning stage of physical aging, thus facilitating further atomic shrinkage of a glassy backbone.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Quantifying the Impacts of Grain-scale Heterogeneity on Mechanical Response

Driven by the exceedingly high computational demands of simulating mechanical response in complex engineered systems with finely resolved finite element models, there is a critical need to optimally reduce the fidelity of such simulations. The minimum required fidelity is constrained by error tolerances on the simulation results, but error bounds are often impossible to obtain a priori. One such source of error is the variability of material properties within a body due to spatially non-uniform processing conditions and inherent stochasticity in material microstructure. This study seeks to quantify the effects of microstructural heterogeneity on component- and system-scale performance to aid in the choice of an appropriate material model and spatial resolution for finite element analysis.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Computer vision models and advanced TEM imaging for microstructures of irradiated AM316 stainless steels

Advancements were made in automating microscopy-based material characterization, particularly in studying irradiation effects on additively manufactured (AM) materials using machine learning (ML) and computer vision (CV). These automation efforts address the challenges of analyzing complex microstructures, accelerating the detection of irradiation-induced defects. Two CV models were developed at Argonne National Laboratory (ANL) to enhance transmission electron microscopy (TEM) analysis of irradiated AM 316 stainless steel. The first model focused on the detection of irradiation-induced dislocation loops, which contribute to material hardening and embrittlement. These loops, categorized as faulted or perfect, were automatically detected and classified using a Mask R-CNN model trained on TEM images from both in-situ and ex-situ ion irradiation experiments. The model achieved high accuracy, with precision, recall, and F1 scores of 0.839, 0.734, and 0.776, respectively, demonstrating its effectiveness in analyzing dislocation loops in irradiated AM materials. The second CV model was developed to analyze the size and wall thickness of dislocation cells in laser powder bed fusion (LPBF) 316 stainless steel. Using a U-Net++ architecture with EfficientNet as the encoder, the model was trained on TEM images to segment and measure cell size and wall thickness.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Electronic and transport properties of polycrystalline Ba{sub 8}Ga{sub 15}Ge{sub 31} type I clathrate prepared by SPS method

Samples of germanium Ba{sub 8}Ga{sub 15}Ge{sub 31} clathrate of type I were prepared using standard metallurgy methods. The structure, microstructure and phase composition of the prepared samples were analyzed by powder X-ray diffraction XRD and scanning electron microscope SEM combined with energy dispersive X-ray analysis EDX. Scanning thermoelectric microprobe STMP was used to characterize uniformity of Seebeck coefficient distribution at different stages of the material synthesis in order to optimize the synthesis method. Electrical conductivity, Seebeck coefficient and thermal conductivity were measured in the temperature range 20-450 Degree-Sign C. Based on the measured electrical properties and Hall carrier concentration n=5-9{center_dot}10{sup 20} cm{sup -3} at room temperature, electron effective mass m{sup Low-Asterisk} was estimated to be between 2.1-3 m{sub 0}. Preliminary FP-LAPW DFT calculations were performed for two chosen high symmetry superstructures Ba{sub 8}Ga{sub 16}Ge{sub 30} and Ba{sub 8}Ga{sub 6}Ge{sub 40} by means of WIEN2K package. Additionally topological analysis of total electron density according to Bader's Quantum Theory of Atoms in Molecules was carried out. The energy band gaps were calculated to be 0.3 eV for Ba{sub 8}Ga{sub 16}Ge{sub 30} and 0.38 eV for Ba{sub 8}Ga{sub 6}Ge{sub 40} which was close to the experimental results for Ba{sub 8}Ga{sub 16}Ge{sub 30}. The observed electrical properties were compared with the electronic band structure calculations, showing good qualitative correlation between the measured transport properties and the theoretical predictions. - Graphical abstract: Scanning thermoelectric microprobe STMP was used to investigate uniformity of the prepared polycrystalline Ba{sub 8}Ga{sub 15}Ge{sub 31} clathrate samples at different synthesis stages. Maps and histograms of the Seebeck coefficient distribution (presented in the picture) for Ba{sub 8}Ga{sub 15}Ge{sub 31} ingot after the first synthesis stage showed it is not uniform. The Seebeck coefficient distribution in the ingot was bimodal. The same analysis for the sample after annealing and sintering showed that the Seebeck coefficient distribution is unimodal. Compared to the ingot from I synthesis stage a significant improvement of material uniformity was observed. Highlights: Black-Right-Pointing-Pointer Scanning thermoelectric microprobe STMP measurements show important uniformity change during sample annealing. Black-Right-Pointing-Pointer Calculated band gap E{sub g} values are close to the reported E{sub g}. Black-Right-Pointing-Pointer Ga/Ge ratio change doesn't affect significantly the bonding properties. Black-Right-Pointing-Pointer Band structure calculations show that bond's character agrees with the Zintl concept.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗