Using Atom Probe Tomography to Elucidate Cu and Si Contaminant Segregation in an Advanced Ni-Based Superalloy
Presented at the CNMS User Meeting 2020, August 10-12, 2020, Virtual Conference, 8/10
Detrois, Martin↗
SEARCH · Engineering Papers
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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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RetSynth aids in the identification of model platform organisms for the biochemical synthesis of MCCI and SI fuels.
Abstract not provided.
Nguyen, Bernard↗
Si Quantum Dots via Rapid Ge Diffusion during High Temperature Oxidation of Si/SiGe Nanostructures.
Abstract not provided.
Turner, Emily↗
Partitioning of Cu and Si Contaminants in a Ni-Based Superalloy and Their Effect on Creep Properties
TMS 2021 Annual Meeting & Exhibition, Virtual, March 15-18, 2021
Detrois, Martin↗
IDENTIFICATION OF ADSORBA TION OF ADSORBATE FT-IR BANDS USING IN-SI -IR BANDS USING IN-SITU TECHNIQUES: Pd SPECIATION AND ADSORPTION CHEMISTRY OF Pd-ZEOLITES FOR PASSIVE NOx ADSORPTION
To meet increasingly stringent automotive emissions standards, further improvements in catalytic converter design are necessary. Current automotive catalyst systems are effective at eliminating emission of nitrogen oxides (NOx) once the catalyst reaches operational temperature (~200 °C). NOx emitted at lower catalyst temperatures now comprises most of the NOx released during a typical test cycle. Referred to as “the cold start problem” this issue has come to the forefront of automotive catalyst development, as mitigating these emissions is necessary to further reduce automotive emissions. Passive NOx adsorbers present an appealing solution to the cold start problem, these being a class of materials that chemisorb exhaust components such as NOx, carbon monoxide (CO) and hydrocarbons at near-ambient temperatures, and then desorb these compounds once the downstream catalyst has reached operational temperature. An effective passive NOx adsorber must have several properties: high NOx adsorption at near-ambient temperatures, near-complete NOx desorption at temperatures within the operational range, high thermal stability, and resistance to automotive exhaust components at high temperatures. The potential environmental impact of such a system is substantial, as NOx emissions currently result in the formation of millions of tons of smog and acid rain each year. Pd-exchanged zeolites have shown promise for deployment as Passive NOx adsorbers, though much remains to be understood about their adsorption chemistry and deactivation. In-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) provides a convenient probe of adsorbed species, most automotive exhaust components possessing IR-active chemical bonds. By examining the evolution of IR bands under various pretreatments and adsorbates, the overall Pd-speciation and adsorptive zeolite sites of each material can be characterized, and the identities of IR bands can be deduced. In this work, microreactor-MS analysis of the adsorption and desorption behavior of these materials was also examined, these results being coupled with in-situ DRIFTS temperature programmed desorption (TPD) to correlate desorption events with specific adsorbed species. A pair of zeolite frameworks of similar Si/Al ratio but differing pore size were examined, Beta zeolite (BEA) and Chabazite (CHA) representing a medium- and small-pore framework, respectively. The effect of Pd-loading on BEA was examined, as well as the various deactivation pathways and active sites of each material.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Effects of Injection Timing and Duration on Fuel-Spray Collapse and Wall Wetting in a Stratified Charge SI Engine.
Abstract not provided.
Kim, Namho↗
Traceability of Surface Longwave Irradiance Measurements to SI Using the IRIS Radiometers: Preprint
The World Radiation Center at PMOD/WRC is operated on behalf of the WMO. The Infrared Radiometry Section of the WRC (WRC-IRS) provides traceability of downwelling atmospheric longwave radiation measured with pyrgeometers by comparison to the World Infrared Standard Group (WISG) [1]. As has been discussed previously [2], the current implementation of the WISG measures lower longwave irradiances than the two candidate reference radiometers IRIS (Infrared Integrating Sphere Radiometer) and the ACP (Absolute Cavity Pyrgeometer). To validate the findings reported in [2], additional measurements since that publication in 2014 have been performed and are discussed in this paper. Specifically, Measurements during cloud-free nights at PMOD/WRC between the WISG and IRIS radiometers, A field campaign at the Atmospheric Radiation Monitoring Site (ARM) at Southern Great Plains, Oklahoma with IRIS, ACP, AERI (Atmospheric Emittance Radiance Interferometer) and WISG traceable pyrgeometers, Laboratory comparison between the reference blackbody of PMOD/WRC with the hemispherical blackbody developed by PTB.
ACR↗
Indirect additive manufacturing process for producing SiC—B4C—Si composites
A method for indirect additive manufacturing of an object constructed of boron carbide, silicon carbide, and free silicon, comprising: (i) producing a porous preform constructed of boron carbide and silicon carbide by an indirect ceramic additive manufacturing (ICAM) process in which particles of a powder mixture become bonded together with an organic binder, wherein the powder mixture comprises: a) boron carbide particles, and b) silicon carbide particles, wherein at least 80 vol % of the silicon carbide particles are larger than the boron carbide particles; and wherein the boron carbide and silicon carbide particles are each included in an amount of 40-60 wt. % of the powder mixture, provided that the foregoing amounts sum to at least 95 wt. %; (ii) subjecting the porous preform to a temperature of 500-900° C. to volatilize the organic binder; and (iii) infiltrating molten silicon into pores of the porous preform to produce the object.
Cramer, Corson L.↗
Grain boundary enhanced UN and U 3 Si 2 pellets with improved oxidation resistance
A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U3Si2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U3Si2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U3Si2.
Lahoda, Edward J.↗
High temperature lightweight Al—Fe—Si based alloys
Described herein are approaches to stabilizing AlFeSi ternary intermetallic compounds while destabilizing competing phases. The inclusion of metals such as Mn, Ni, Co, Cu, or Zn to produce quaternary systems accomplishes this problem associated with AlFeSi ternary intermetallic compounds.
Soto Medina, Sujeily↗
The Development of a Stabilized SEI Layer for Si‐Containing Lithium-Ion Battery Anodes
Explore the source record for details and available documents.
25 ENERGY STORAGE↗
Evaluation of Thermal Scattering Law for U 3 Si 2 Using Temperature-Dependent Phonon Density of States
The thermal scattering law for uranium silicide, a candidate material for high-density nuclear fuel, was evaluated from the temperature-dependent phonon density of states obtained using the quasi-harmonic approximation. For uranium silicide model systems of various volumes near the equilibrium volume, Hellmann-Feynman forces were calculated by performing ab initio lattice dynamics simulations based on density functional theory. Subsequently, the quasi-harmonic approximation was applied by interpolating the results of the harmonic approximation for each volume system. As a sensitivity test, the phonon density of states was calculated for the structures with temperature-dependent volumes at 298 K and 1000 K, obtained by the quasi-harmonic approximation, and the corresponding thermal neutron scattering cross section was evaluated. The temperature-dependent volume and heat capacity of uranium silicide obtained by the quasi-harmonic approximation showed reasonable agreement with experimental data while lattice thermal expansion showed deviation from experimental observations. Thermal scattering cross sections evaluated from 0 K and temperature-dependent phonon density of states exhibited differences of up to 4.1% at 1000 K. This study examines the impact of temperature on the thermal scattering law, employing ab initio lattice dynamics simulations through the quasi-harmonic approximation.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Materials Data on Na4Ga4Si19 by Materials Project
NaNa7(Ga4Si19)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional and consists of one sodium molecule and one Na7(Ga4Si19)2 framework. In the Na7(Ga4Si19)2 framework, there are seven inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 8-coordinate geometry to seventeen Si+0.63- atoms. There are a spread of Na–Si bond distances ranging from 3.29–3.43 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Si+0.63- atoms. There are a spread of Na–Si bond distances ranging from 3.50–3.54 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Si+0.63- atoms. There are a spread of Na–Si bond distances ranging from 3.49–3.52 Å. In the fourth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Si+0.63- atoms. There are a spread of Na–Si bond distances ranging from 3.51–3.53 Å. In the fifth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven Si+0.63- atoms. There are a spread of Na–Si bond distances ranging from 3.51–3.53 Å. In the sixth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven Si+0.63- atoms. There are a spread of Na–Si bond distances ranging from 3.50–3.52 Å. In the seventh Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eighteen Si+0.63- atoms. There are a spread of Na–Si bond distances ranging from 3.30–3.42 Å. There are eight inequivalent Ga2+ sites. In the first Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share a cornercorner with one GaSi4 tetrahedra and corners with three SiNa3Si4 tetrahedra. There are a spread of Ga–Si bond distances ranging from 2.43–2.47 Å. In the second Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share corners with two GaSi4 tetrahedra and corners with two SiNa2Si4 tetrahedra. There are two shorter (2.44 Å) and two longer (2.47 Å) Ga–Si bond lengths. In the third Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share corners with two GaSi4 tetrahedra and corners with two SiNa3Si4 tetrahedra. There are a spread of Ga–Si bond distances ranging from 2.44–2.48 Å. In the fourth Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share corners with two GaSi4 tetrahedra and corners with five SiNa3Si4 tetrahedra. There are a spread of Ga–Si bond distances ranging from 2.44–2.47 Å. In the fifth Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share corners with three SiNa2Si4 tetrahedra and corners with four GaSi4 tetrahedra. There are three shorter (2.45 Å) and one longer (2.46 Å) Ga–Si bond lengths. In the sixth Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share corners with two SiNa3Si4 tetrahedra and corners with three GaSi4 tetrahedra. There are a spread of Ga–Si bond distances ranging from 2.44–2.47 Å. In the seventh Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share corners with two GaSi4 tetrahedra and corners with three SiNa3Si4 tetrahedra. There are a spread of Ga–Si bond distances ranging from 2.44–2.46 Å. In the eighth Ga2+ site, Ga2+ is bonded to four Si+0.63- atoms to form GaSi4 tetrahedra that share corners with two GaSi4 tetrahedra and corners with five SiNa2Si4 tetrahedra. There are two shorter (2.45 Å) and two longer (2.46 Å) Ga–Si bond lengths. There are thirty-eight inequivalent Si+0.63- sites. In the first Si+0.63- site, Si+0.63- is bonded in a tetrahedral geometry to one Ga2+ and three Si+0.63- atoms. There are two shorter (2.41 Å) and one longer (2.42 Å) Si–Si bond lengths. In the second Si+0.63- site, Si+0.63- is bonded in a tetrahedral geometry to two Ga2+ and two Si+0.63- atoms. Both Si–Si bond lengths are 2.40 Å. In the third Si+0.63- site, Si+0.63- is bonded in a tetrahedral geometry to two Ga2+ and two Si+0.63- atoms. There are one shorter (2.40 Å) and one longer (2.41 Å) Si–Si bond lengths. In the fourth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to one Na1+, one Ga2+, and three Si+0.63- atoms. There are a spread of Si–Si bond distances ranging from 2.35–2.39 Å. In the fifth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+, two Ga2+, and two Si+0.63- atoms. There are one shorter (2.35 Å) and one longer (2.36 Å) Si–Si bond lengths. In the sixth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. There are a spread of Si–Si bond distances ranging from 2.36–2.41 Å. In the seventh Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. There are a spread of Si–Si bond distances ranging from 2.38–2.40 Å. In the eighth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. There are one shorter (2.39 Å) and two longer (2.40 Å) Si–Si bond lengths. In the ninth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to one Na1+, one Ga2+, and three Si+0.63- atoms. There are one shorter (2.38 Å) and one longer (2.40 Å) Si–Si bond lengths. In the tenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+, one Ga2+, and three Si+0.63- atoms. There are one shorter (2.37 Å) and one longer (2.39 Å) Si–Si bond lengths. In the eleventh Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. There are two shorter (2.38 Å) and one longer (2.40 Å) Si–Si bond lengths. In the twelfth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+, one Ga2+, and three Si+0.63- atoms. There are one shorter (2.36 Å) and two longer (2.37 Å) Si–Si bond lengths. In the thirteenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. All Si–Si bond lengths are 2.39 Å. In the fourteenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. There are a spread of Si–Si bond distances ranging from 2.38–2.40 Å. In the fifteenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+, two Ga2+, and two Si+0.63- atoms. There are one shorter (2.33 Å) and one longer (2.36 Å) Si–Si bond lengths. In the sixteenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. There are a spread of Si–Si bond distances ranging from 2.37–2.40 Å. In the seventeenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+, one Ga2+, and three Si+0.63- atoms. Both Si–Si bond lengths are 2.38 Å. In the eighteenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+ and four Si+0.63- atoms. There are two shorter (2.38 Å) and one longer (2.39 Å) Si–Si bond lengths. In the nineteenth Si+0.63- site, Si+0.63- is bonded in a 5-coordinate geometry to one Na1+, one Ga2+, and three Si+0.63- atoms. There are one shorter (2.38 Å) and one longer (2.39 Å) Si–Si bond lengths. In the twentieth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, two Ga2+, and two Si+0.63- atoms. In the twenty-first Si+0.63- site, Si+0.63- is bonded to three Na1+ and four Si+0.63- atoms to form distorted SiNa3Si4 tetrahedra that share corners with two GaSi4 tetrahedra, corners with five SiNa2Si4 tetrahedra, and an edgeedge with one SiNa3Si4 tetrahedra. The Si–Si bond length is 2.43 Å. In the twenty-second Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, one Ga2+, and three Si+0.63- atoms. In the twenty-third Si+0.63- site, Si+0.63- is bonded to two Na1+ and four Si+0.63- atoms to form distorted SiNa2Si4 tetrahedra that share corners with four GaSi4 tetrahedra and corners with four SiNa3Si4 tetrahedra. The Si–Si bond length is 2.43 Å. In the twenty-fourth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to two Na1+, one Ga2+, and three Si+0.63- atoms. In the twenty-fifth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to two Na1+, two Ga2+, and two Si+0.63- atoms. In the twenty-sixth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, one Ga2+, and three Si+0.63- atoms. The Si–Si bond length is 2.43 Å. In the twenty-seventh Si+0.63- site, Si+0.63- is bonded to three Na1+ and four Si+0.63- atoms to form distorted SiNa3Si4 tetrahedra that share corners with five GaSi4 tetrahedra, corners with six SiNa2Si4 tetrahedra, and an edgeedge with one SiNa3Si4 tetrahedra. In the twenty-eighth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, two Ga2+, and two Si+0.63- atoms. In the twenty-ninth Si+0.63- site, Si+0.63- is bonded to two Na1+ and four Si+0.63- atoms to form distorted SiNa2Si4 tetrahedra that share corners with three SiNa2Si4 tetrahedra, corners with four GaSi4 tetrahedra, and edges with two SiNa3Si4 tetrahedra. The Si–Si bond length is 2.44 Å. In the thirtieth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to two Na1+, one Ga2+, and three Si+0.63- atoms. In the thirty-first Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to two Na1+, two Ga2+, and two Si+0.63- atoms. In the thirty-second Si+0.63- site, Si+0.63- is bonded to three Na1+ and four Si+0.63- atoms to form distorted SiNa3Si4 tetrahedra that share corners with three GaSi4 tetrahedra, corners with five SiNa3Si4 tetrahedra, and an edgeedge with one SiNa2Si4 tetrahedra. The Si–Si bond length is 2.43 Å. In the thirty-third Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, one Ga2+, and three Si+0.63- atoms. In the thirty-fourth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, two Ga2+, and two Si+0.63- atoms. In the thirty-fifth Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, one Ga2+, and three Si+0.63- atoms. The Si–Si bond length is 2.42 Å. In the thirty-sixth Si+0.63- site, Si+0.63- is bonded to three Na1+ and four Si+0.63- atoms to form distorted SiNa3Si4 tetrahedra that share corners with four GaSi4 tetrahedra, corners with five SiNa3Si4 tetrahedra, an edgeedge with one SiNa2Si4 tetrahedra, and a faceface with one SiNa3Si4 tetrahedra. In the thirty-seventh Si+0.63- site, Si+0.63- is bonded in a 4-coordinate geometry to three Na1+, one Ga2+, and three Si+0.63- atoms. The Si–Si bond length is 2.42 Å. In the thirty-eighth Si+0.63- site, Si+0.63- is bonded to three Na1+ and four Si+0.63- atoms to form distorted SiNa3Si4 tetrahedra that share corners with three GaSi4 tetrahedra, corners with six SiNa3Si4 tetrahedra, and a faceface with one SiNa3Si4 tetrahedra.
36 MATERIALS SCIENCE↗
Materials Data on Al4Si19 by Materials Project
Al4Si19 is beta beryllia-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiSi4 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.48–2.51 Å. In the second Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiSi4 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.46–2.54 Å. In the third Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiSi4 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.49–2.51 Å. In the fourth Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiAlSi3 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.46–2.52 Å. In the fifth Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiSi4 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.49–2.56 Å. In the sixth Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share corners with three AlSi4 tetrahedra and corners with nine SiAl2Si2 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.47–2.57 Å. In the seventh Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiSi4 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.44–2.53 Å. In the eighth Al3+ site, Al3+ is bonded to four Si+0.63- atoms to form AlSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiSi4 tetrahedra. There are three shorter (2.49 Å) and one longer (2.52 Å) Al–Si bond lengths. There are thirty-eight inequivalent Si+0.63- sites. In the first Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form corner-sharing SiAlSi3 tetrahedra. There are one shorter (2.37 Å) and two longer (2.38 Å) Si–Si bond lengths. In the second Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form corner-sharing SiAl2Si2 tetrahedra. Both Si–Si bond lengths are 2.37 Å. In the third Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form corner-sharing SiAl2Si2 tetrahedra. There are one shorter (2.39 Å) and one longer (2.40 Å) Si–Si bond lengths. In the fourth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form SiAlSi3 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiSi4 tetrahedra. There are one shorter (2.35 Å) and two longer (2.37 Å) Si–Si bond lengths. In the fifth Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form SiAl2Si2 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiAl2Si2 tetrahedra. There are one shorter (2.35 Å) and one longer (2.37 Å) Si–Si bond lengths. In the sixth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with three AlSi4 tetrahedra and corners with nine SiAlSi3 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.35–2.38 Å. In the seventh Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiAl2Si2 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.36–2.40 Å. In the eighth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with three AlSi4 tetrahedra and corners with nine SiAlSi3 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.36–2.39 Å. In the ninth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form SiAlSi3 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiAlSi3 tetrahedra. Both Si–Si bond lengths are 2.37 Å. In the tenth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form SiAlSi3 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiAl2Si2 tetrahedra. There are one shorter (2.35 Å) and one longer (2.37 Å) Si–Si bond lengths. In the eleventh Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiAl2Si2 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.36–2.40 Å. In the twelfth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form SiAlSi3 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiAl2Si2 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.33–2.39 Å. In the thirteenth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiSi4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.36–2.40 Å. In the fourteenth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiAlSi3 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.36–2.40 Å. In the fifteenth Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form SiAl2Si2 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiAl2Si2 tetrahedra. There are one shorter (2.33 Å) and one longer (2.34 Å) Si–Si bond lengths. In the sixteenth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiAlSi3 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.36–2.40 Å. In the seventeenth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form SiAlSi3 tetrahedra that share corners with three AlSi4 tetrahedra and corners with nine SiAl2Si2 tetrahedra. There are one shorter (2.36 Å) and one longer (2.38 Å) Si–Si bond lengths. In the eighteenth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiAl2Si2 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.36–2.38 Å. In the nineteenth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form SiAlSi3 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiSi4 tetrahedra. There are one shorter (2.34 Å) and one longer (2.38 Å) Si–Si bond lengths. In the twentieth Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form SiAl2Si2 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiAl2Si2 tetrahedra. In the twenty-first Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with two AlSi4 tetrahedra and corners with ten SiAlSi3 tetrahedra. The Si–Si bond length is 2.36 Å. In the twenty-second Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form distorted SiAlSi3 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiAl2Si2 tetrahedra. In the twenty-third Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiAlSi3 tetrahedra. The Si–Si bond length is 2.37 Å. In the twenty-fourth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form distorted corner-sharing SiAlSi3 tetrahedra. In the twenty-fifth Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form SiAl2Si2 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiSi4 tetrahedra. In the twenty-sixth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form distorted SiAlSi3 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiAl2Si2 tetrahedra. The Si–Si bond length is 2.37 Å. In the twenty-seventh Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with five AlSi4 tetrahedra and corners with seven SiAl2Si2 tetrahedra. In the twenty-eighth Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form corner-sharing SiAl2Si2 tetrahedra. In the twenty-ninth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiSi4 tetrahedra. The Si–Si bond length is 2.38 Å. In the thirtieth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form distorted SiAlSi3 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiAlSi3 tetrahedra. In the thirty-first Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form corner-sharing SiAl2Si2 tetrahedra. In the thirty-second Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with three AlSi4 tetrahedra and corners with nine SiAlSi3 tetrahedra. The Si–Si bond length is 2.36 Å. In the thirty-third Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form distorted SiAlSi3 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiAl2Si2 tetrahedra. In the thirty-fourth Si+0.63- site, Si+0.63- is bonded to two Al3+ and two Si+0.63- atoms to form SiAl2Si2 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiAl2Si2 tetrahedra. In the thirty-fifth Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form distorted SiAlSi3 tetrahedra that share a cornercorner with one AlSi4 tetrahedra and corners with eleven SiSi4 tetrahedra. The Si–Si bond length is 2.37 Å. In the thirty-sixth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with four AlSi4 tetrahedra and corners with eight SiSi4 tetrahedra. In the thirty-seventh Si+0.63- site, Si+0.63- is bonded to one Al3+ and three Si+0.63- atoms to form corner-sharing SiAlSi3 tetrahedra. The Si–Si bond length is 2.36 Å. In the thirty-eighth Si+0.63- site, Si+0.63- is bonded to four Si+0.63- atoms to form SiSi4 tetrahedra that share corners with three AlSi4 tetrahedra and corners with nine SiAlSi3 tetrahedra.
36 MATERIALS SCIENCE↗