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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Sr(IO)2 by Materials Project

Sr(OI)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Sr sites. In the first Sr site, Sr is bonded to four O and three I atoms to form distorted edge-sharing SrI3O4 pentagonal bipyramids. There are a spread of Sr–O bond distances ranging from 2.47–2.50 Å. There are a spread of Sr–I bond distances ranging from 3.35–3.51 Å. In the second Sr site, Sr is bonded in a 2-coordinate geometry to four O and five I atoms. There are a spread of Sr–O bond distances ranging from 2.48–2.72 Å. There are a spread of Sr–I bond distances ranging from 3.40–4.02 Å. In the third Sr site, Sr is bonded in a 2-coordinate geometry to four O and four I atoms. There are a spread of Sr–O bond distances ranging from 2.48–2.70 Å. There are a spread of Sr–I bond distances ranging from 3.43–3.65 Å. In the fourth Sr site, Sr is bonded in a 4-coordinate geometry to four O and four I atoms. There are a spread of Sr–O bond distances ranging from 2.46–2.52 Å. There are a spread of Sr–I bond distances ranging from 3.31–3.94 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. The O–O bond length is 1.38 Å. In the second O site, O is bonded in a T-shaped geometry to two equivalent Sr and one O atom. The O–O bond length is 1.40 Å. In the third O site, O is bonded in a distorted T-shaped geometry to two equivalent Sr and one O atom. The O–O bond length is 1.42 Å. In the fourth O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. The O–O bond length is 1.37 Å. In the fifth O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. In the sixth O site, O is bonded in a 4-coordinate geometry to two equivalent Sr, one O, and one I atom. The O–I bond length is 2.36 Å. In the seventh O site, O is bonded in a 4-coordinate geometry to two equivalent Sr, one O, and one I atom. The O–I bond length is 2.34 Å. In the eighth O site, O is bonded in a distorted T-shaped geometry to two equivalent Sr and one O atom. There are eight inequivalent I sites. In the first I site, I is bonded in a 4-coordinate geometry to three Sr and one I atom. The I–I bond length is 3.34 Å. In the second I site, I is bonded in a distorted single-bond geometry to one Sr, one O, and one I atom. The I–I bond length is 3.17 Å. In the third I site, I is bonded in a distorted single-bond geometry to one Sr, one O, and one I atom. In the fourth I site, I is bonded in a 2-coordinate geometry to three Sr and one I atom. In the fifth I site, I is bonded in a distorted bent 120 degrees geometry to two Sr and one I atom. The I–I bond length is 3.29 Å. In the sixth I site, I is bonded in a 2-coordinate geometry to two Sr and one I atom. The I–I bond length is 3.29 Å. In the seventh I site, I is bonded in a 2-coordinate geometry to two Sr and one I atom. In the eighth I site, I is bonded in a distorted bent 120 degrees geometry to two Sr and one I atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(IO)2 by Materials Project

Sr(OI)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Sr sites. In the first Sr site, Sr is bonded in a 9-coordinate geometry to four O and four I atoms. There are a spread of Sr–O bond distances ranging from 2.50–2.53 Å. There are a spread of Sr–I bond distances ranging from 3.43–3.71 Å. In the second Sr site, Sr is bonded in a 9-coordinate geometry to four O and five I atoms. There are a spread of Sr–O bond distances ranging from 2.51–2.53 Å. There are a spread of Sr–I bond distances ranging from 3.47–3.83 Å. In the third Sr site, Sr is bonded in a 9-coordinate geometry to four O and four I atoms. There are a spread of Sr–O bond distances ranging from 2.51–2.53 Å. There are a spread of Sr–I bond distances ranging from 3.43–3.70 Å. In the fourth Sr site, Sr is bonded in a 9-coordinate geometry to four O and five I atoms. There are a spread of Sr–O bond distances ranging from 2.50–2.53 Å. There are a spread of Sr–I bond distances ranging from 3.46–3.85 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. The O–O bond length is 1.38 Å. In the second O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. The O–O bond length is 1.37 Å. In the third O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. The O–O bond length is 1.38 Å. In the fourth O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. The O–O bond length is 1.37 Å. In the fifth O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. In the sixth O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. In the seventh O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. In the eighth O site, O is bonded in a 3-coordinate geometry to two equivalent Sr and one O atom. There are eight inequivalent I sites. In the first I site, I is bonded in a distorted water-like geometry to two Sr and one I atom. The I–I bond length is 3.31 Å. In the second I site, I is bonded in a 2-coordinate geometry to three Sr and one I atom. The I–I bond length is 3.27 Å. In the third I site, I is bonded in a distorted water-like geometry to two Sr and one I atom. The I–I bond length is 3.28 Å. In the fourth I site, I is bonded in a 2-coordinate geometry to three Sr and one I atom. The I–I bond length is 3.30 Å. In the fifth I site, I is bonded in a distorted rectangular see-saw-like geometry to two Sr and two I atoms. The I–I bond length is 2.88 Å. In the sixth I site, I is bonded in a 4-coordinate geometry to two Sr and two I atoms. The I–I bond length is 2.88 Å. In the seventh I site, I is bonded in a distorted rectangular see-saw-like geometry to two Sr and two I atoms. In the eighth I site, I is bonded in a 4-coordinate geometry to two Sr and two I atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr2Cu(IO)2 by Materials Project

Sr2Cu(OI)2 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two Sr2Cu(OI)2 sheets oriented in the (0, 0, 1) direction. Sr2+ is bonded in a 8-coordinate geometry to four equivalent O2- and four equivalent I1- atoms. All Sr–O bond lengths are 2.64 Å. All Sr–I bond lengths are 3.37 Å. Cu2+ is bonded in a square co-planar geometry to four equivalent O2- and two equivalent I1- atoms. All Cu–O bond lengths are 2.03 Å. Both Cu–I bond lengths are 3.44 Å. O2- is bonded to four equivalent Sr2+ and two equivalent Cu2+ atoms to form a mixture of edge, face, and corner-sharing OSr4Cu2 octahedra. The corner-sharing octahedral tilt angles are 0°. I1- is bonded in a 5-coordinate geometry to four equivalent Sr2+ and one Cu2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Environmental remediation with functional aerogels and xerogels

Several different types of aerogel and/or xerogel scaffolds have been demonstrated as effective sorbents for the capture and immobilization of radionuclides in gaseous form [e.g., iodine gas or I2(g), Xe] as well as ionic form (e.g., Ce4+, Cs+, I–, IO3-, Rb+, Sr2+, 99Tc7+, and U6+). These scaffolds have unique properties, which include high specific surface areas, high pore volumes, varieties of pore sizes, and functionalities that provide methods for binding radionuclides through physisorption, chemisorption, or a combination thereof. This combination of properties and functionalities make these types of materials ideal scaffolds for use as sorbents for capturing radionuclides. The primary base materials that will be discussed in this chapter include Ag0-functionalized silica aerogels, Ag+-impregnated aluminosilicate aerogels, Ag0-functionalized aluminosilicate aerogels, metal-impregnated (non-Ag) aluminosilicate aerogels and xerogels, sulfide-based aerogels, and carbon-based aerogel composites. For the capture of I2(g), the materials reported herein show some of the highest iodine loadings ever reported for inorganic sorbents. For the capture of ionic species, these materials also show promise to be some of the next generations of materials for active radionuclide remediation. This progress report will describe how these materials are fabricated, the general properties of these materials, as well as an overview of how they have been used for different applications in environmental remediation of radionuclides.

aerogel, xerogel, iodine, radionuclide remediation↗
NASA NTRS1997

Numerical Simulation of Rotation-Driven Plasma Transport In the Jovian Magnetosphere

A Jupiter version of the Rice Convection Model (RCM-J) was developed with support of an earlier NASA SR&T grant. The conversion from Earth to Jupiter included adding currents driven by centrifugal force, reversing the planetary magnetic field, and rescaling various parameters. A series of informative runs was carried out, all of them solving initial value problems. The simulations followed an initial plasma torus configuration as it fell apart by interchange instability. Some conclusions from the simulations were the following: 1. We confirmed that, for conventional values of the torus density and ionospheric conductance, the torus disintegrates by interchange instability on a time scale of approx. one day, which is 1-2 orders of magnitude shorter than the best estimates of the average residence time of plasma in the torus. 2. In the model, the instability could be slowed to an arbitrary degree by the addition of sufficient impounding energetic particles, as suggested earlier by Siscoe et al (1981). However, the observed energetic particles do not seem sufficient to guarantee impoundment (e.g., Mauk et al., 1996). 3. Whether inhibited by impoundment or not, the interchange was found to proceed by the formation of long fingers, which get thinner as they get longer. This picture differed dramatically from the conventional radial-diffusion picture (e.g., Siscoe and Summers (1981)), more superficially with the outward-moving-blob picture (Pontius and Hill, 1989). The obvious limitation of the original RCM-J was that it could not represent a plasma source. We could represent the decay of a pre-existing torus, but we could not represent the way ionization of material from Io continually replenishes the plasma. We consequently were precluded from studying a whole set of fundamental issues of torus theory, including whether the system can come to a steady state.

Wolf, Richard A.↗