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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Sr(CO2)3 by Materials Project

Sr(CO2)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.57–2.84 Å. There are three inequivalent C+3.33+ sites. In the first C+3.33+ site, C+3.33+ is bonded in a bent 150 degrees geometry to two O2- atoms. There is one shorter (1.22 Å) and one longer (1.23 Å) C–O bond length. In the second C+3.33+ site, C+3.33+ is bonded in a bent 150 degrees geometry to two O2- atoms. There is one shorter (1.21 Å) and one longer (1.23 Å) C–O bond length. In the third C+3.33+ site, C+3.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both C–O bond lengths are 1.27 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C+3.33+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+3.33+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C+3.33+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C+3.33+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+ and one C+3.33+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C+3.33+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2020

Structural evolution, electrochemical kinetic properties, and stability of A-site doped perovskite Sr(1-x)Yb(x)CoO(3-δ)

Mixed ionic and electronic conducting (MIEC) perovskite SrCoO(3-δ) is a widely studied (electro)catalyst for the oxygen reduction reaction (ORR) and possesses different crystal structures at different temperatures. These temperature dependent phase transitions significantly impact the ordering of oxygen vacancies and electrochemical kinetic properties as well as the reliability of the related devices. Some of the crystal structures formed, e.g. hexagonal phases, turn out to be almost impermeable to oxygen gas. Therefore, it is important to stabilize the crystal structure of SrCoO(3-δ) that favors the ORR over a wide temperature range. Herein, the partial substitution of the A-site Sr with Yb is systematically studied, including synthesis, characterization and analysis of structural evolution, electrochemical kinetic properties, thermal stability, and stability in a CO2-containing atmosphere. The results indicate that Sr(0.90)Yb(0.10)CoO(3-δ) is able to stabilize the tetragonal crystal structure with less ordered oxygen vacancies, leading to polarization resistances of 0.051, 0.115 and 0.272 U sq.cm at 750, 700 and 650 °C, respectively, on symmetrical cells. Sr(0.90)Yb(0.10)CoO(3-δ) demonstrates a very stable surface oxygen vacancy distribution and electronic structure near oxygen vacancies but dissociation of adsorbed oxygen molecules into atomic oxygen is affected by surface Sr segregation, and polarization resistance degradation is mainly induced by surface Sr segregation. Furthermore, Sr(0.90)Yb(0.10)CoO(3-δ) exhibits excellent thermal stability as well as excellent recovery stability and improved polarization performance after a few pure air/CO2-containing air treatment cycles at 700 °C. However, a hysteresis behavior of polarization performance is observed at 650 °C during gas cycling treatment, which may cause long-term degradation of the Sr(0.90)Yb(0.10)CoO(3-δ) electrode. The different polarization behaviors during gas cycling treatment are induced by different sensitivities of the formed surface strontium carbonate and chemisorbed surface oxo-carbonaceous species to different operating temperatures.

electrochemical kinetic↗
DOE OSTI2020

Materials Data on SrCo2(AsO4)2 by Materials Project

SrCo2(AsO4)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Sr2+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Sr–O bond distances ranging from 1.76–2.34 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Co–O bond distances ranging from 1.29–2.28 Å. In the second Co2+ site, Co2+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Co–O bond distances ranging from 1.73–2.44 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of As–O bond distances ranging from 1.17–2.46 Å. In the second As5+ site, As5+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of As–O bond distances ranging from 1.69–2.50 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Co2+ and one As5+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one As5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Co2+ and two As5+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Co2+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to one Sr2+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to one Co2+ and one As5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+ and one As5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+ and one As5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr4Co(IrO4)3 by Materials Project

Sr4Co(IrO4)3 is Orthorhombic Perovskite-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.48–2.81 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.46–2.82 Å. There are three inequivalent Ir+4.67+ sites. In the first Ir+4.67+ site, Ir+4.67+ is bonded to six O2- atoms to form corner-sharing IrO6 octahedra. The corner-sharing octahedra tilt angles range from 25–27°. There are two shorter (2.04 Å) and four longer (2.05 Å) Ir–O bond lengths. In the second Ir+4.67+ site, Ir+4.67+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with two equivalent CoO6 octahedra and corners with four equivalent IrO6 octahedra. The corner-sharing octahedra tilt angles range from 18–27°. There are two shorter (1.95 Å) and four longer (2.05 Å) Ir–O bond lengths. In the third Ir+4.67+ site, Ir+4.67+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with two equivalent IrO6 octahedra and corners with four equivalent CoO6 octahedra. The corner-sharing octahedra tilt angles range from 19–25°. There are a spread of Ir–O bond distances ranging from 1.97–2.03 Å. Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six IrO6 octahedra. The corner-sharing octahedra tilt angles range from 18–22°. There are two shorter (2.06 Å) and four longer (2.08 Å) Co–O bond lengths. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+, one Ir+4.67+, and one Co2+ atom. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+ and two Ir+4.67+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+ and two Ir+4.67+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+, one Ir+4.67+, and one Co2+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Sr2+ and two Ir+4.67+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Sr2+, one Ir+4.67+, and one Co2+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1977

Simplified methods for calculating photodissociation rates

Simplified methods for calculating the transmission of solar UV radiation and the dissociation coefficients of various molecules are compared. A significant difference sometimes appears in calculations of the individual band, but the total transmission and the total dissociation coefficients integrated over the entire SR (solar radiation) band region agree well between the methods. The ambiguities in the solar flux data affect the calculated dissociation coefficients more strongly than does the method. A simpler method is developed for the purpose of reducing the computation time and computer memory size necessary for storing coefficients of the equations. The new method can reduce the computation time by a factor of more than 3 and the memory size by a factor of more than 50 compared with the Hudson-Mahle method, and yet the result agrees within 10 percent (in most cases much less) with the original Hudson-Mahle results, except for H2O and CO2. A revised method is necessary for these two molecules, whose absorption cross sections change very rapidly over the SR band spectral range.

Shimazaki, T.↗
NASA NTRS1983

Modelling atmospheric aerosol backscatter at CO2 laser wavelengths. I - Aerosol properties, modeling techniques, and associated problems. II - Modeled values in the atmosphere. III - Effects of changes in wavelength and ambient conditions

The various methods of calculating the atmospheric aerosol backscattering function, beta(CO2), both from measured aerosol characteristics and from optical measurements made at other wavelengths, are discussed in detail, with limits placed on their accuracy. The most significant factor in determining beta(CO2) is found to be the aerosol size distribution and concentration; this should be known accurately for particle radii up to at least 1 micron for stratospheric particles and 5 microns for tropospheric particles. Results are then presented from the modeling of the aerosol backscattering function at a wavelength of 10.6 microns in the lowest 20 km of the atmosphere. It is found that beta(CO2) varies from 10 to the -6th per m per sr in the planetary boundary layer to less than 10 to the -11th per m per sr in the stratosphere. It is next shown that, with the exception of (NH4)2SO4-containing aerosols, whose size distributions have relatively large numbers of small particles, the variation of backscattering with CO2 wavelength is less than a factor of approximately 3. For such (NH4)2SO4 aerosol distributions, however, the variation of backscatter function with CO2 wavelengths between 9.1 and 11.1 microns may reach one order of magnitude.

Kent, G.S.↗
DOE OSTI2020

Materials Data on SrLaTaCoO6 by Materials Project

SrLaTaCoO6 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are six inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form distorted SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with three equivalent LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.69–3.12 Å. In the second Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with three equivalent LaO12 cuboctahedra, faces with three equivalent CoO6 octahedra, and faces with five TaO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.76–2.90 Å. In the third Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with six LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are nine shorter (2.84 Å) and three longer (2.86 Å) Sr–O bond lengths. In the fourth Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with six equivalent SrO12 cuboctahedra, corners with six LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with two CoO6 octahedra, and faces with six TaO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.84–2.91 Å. In the fifth Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with six LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.83–2.86 Å. In the sixth Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with six LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.83–2.87 Å. There are six inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with three equivalent SrO12 cuboctahedra, corners with nine LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of La–O bond distances ranging from 2.82–2.84 Å. In the second La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with twelve LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are six shorter (2.84 Å) and six longer (2.85 Å) La–O bond lengths. In the third La3+ site, La3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are three shorter (2.45 Å) and six longer (2.87 Å) La–O bond lengths. In the fourth La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with twelve LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of La–O bond distances ranging from 2.83–2.86 Å. In the fifth La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with twelve LaO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of La–O bond distances ranging from 2.83–2.85 Å. In the sixth La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with three equivalent SrO12 cuboctahedra, corners with nine LaO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with two TaO6 octahedra, and faces with six CoO6 octahedra. There are nine shorter (2.84 Å) and three longer (2.85 Å) La–O bond lengths. There are six inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, a faceface with one LaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There is three shorter (1.93 Å) and three longer (2.05 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, a faceface with one LaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There is three shorter (1.94 Å) and three longer (2.05 Å) Ta–O bond length. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Ta–O bond lengths are 1.98 Å. In the fourth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is three shorter (1.98 Å) and three longer (1.99 Å) Ta–O bond length. In the fifth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Ta–O bond lengths are 1.98 Å. In the sixth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, a faceface with one SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There is three shorter (1.96 Å) and three longer (2.00 Å) Ta–O bond length. There are six inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, faces with three equivalent LaO12 cuboctahedra, and faces with four SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–5°. There are three shorter (2.02 Å) and three longer (2.06 Å) Co–O bond lengths. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with three equivalent LaO12 cuboctahedra, and faces with five SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. All Co–O bond lengths are 2.04 Å. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (2.04 Å) and three longer (2.05 Å) Co–O bond lengths. In the fourth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Co–O bond lengths are 2.04 Å. In the fifth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with three equivalent SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (2.04 Å) and three longer (2.05 Å) Co–O bond lengths. In the sixth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, a faceface with one SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are three shorter (1.98 Å) and three longer (2.06 Å) Co–O bond lengths. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three Sr2+, one La3+, one Ta5+, and one Co2+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to three Sr2+, one La3+, one Ta5+, and one Co2+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to two Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two La3+, one Ta5+, and one Co2+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to two Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the seventh O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two La3+, one Ta5+, and one Co2+ atom. In the eighth O2- site, O2- is bonded in a distorted linear geometry to two Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the ninth O2- site, O2- is bonded in a distorted linear geometry to one Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the tenth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two La3+, one Ta5+, and one Co2+ atom. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to four La3+, one Ta5+, and one Co2+ atom. In the twelfth O2- site, O2- is bonded to one Sr2+, three La3+, and two Co2+ atoms to form a mixture of distorted corner and face-sharing OSrLa3Co2 octahedra. The corner-sharing octahedra tilt angles range from 3–60°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrCo2H2(SeO3)4 by Materials Project

SrCo2H2(SeO3)4 crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–2.82 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.58–2.77 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Co–O bond distances ranging from 2.09–2.19 Å. In the second Co2+ site, Co2+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Co–O bond distances ranging from 2.09–2.18 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.60 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. There are four inequivalent Se4+ sites. In the first Se4+ site, Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.73–1.76 Å. In the second Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. All Se–O bond lengths are 1.74 Å. In the third Se4+ site, Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.69–1.87 Å. In the fourth Se4+ site, Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.69–1.88 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one Co2+, and one Se4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one Co2+, and one Se4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Co2+, one H1+, and one Se4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one Co2+, and one Se4+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Sr2+, one Co2+, and one Se4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+, one Co2+, and one Se4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Co2+ and one Se4+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one Co2+, and one Se4+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to one Co2+, one H1+, and one Se4+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Co2+ and one Se4+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Co2+, and one Se4+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to one Co2+, one H1+, and one Se4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrCo3(P2O7)2 by Materials Project

SrCo3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Sr2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.59–2.76 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six PO4 tetrahedra and edges with two equivalent CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.10–2.17 Å. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six PO4 tetrahedra and edges with two CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.10–2.26 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with five CoO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–60°. There are a spread of P–O bond distances ranging from 1.53–1.61 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–59°. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, two Co2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Co2+ and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+, one Co2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Co2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Co2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Co2+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr3Nb2CoO9 by Materials Project

Sr3Nb2CoO9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.47–3.08 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.45–3.11 Å. In the third Sr2+ site, Sr2+ is bonded in a 2-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.11 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Nb–O bond distances ranging from 1.94–2.00 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra and corners with two equivalent CoO6 octahedra. The corner-sharing octahedra tilt angles range from 3–24°. There are a spread of Nb–O bond distances ranging from 1.97–2.04 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.88 Å) and two longer (1.90 Å) Co–O bond length. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 3–19°. There is two shorter (1.98 Å) and four longer (1.99 Å) Co–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+, one Nb5+, and one Co2+ atom. In the second O2- site, O2- is bonded in a water-like geometry to one Nb5+ and one Co2+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to four Sr2+ and one Co2+ atom. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to four Sr2+, one Nb5+, and one Co2+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three Sr2+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Nb5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two equivalent Nb5+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to four Sr2+, one Nb5+, and one Co2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrCo2(AsO4)2 by Materials Project

SrCo2(AsO4)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Sr2+ is bonded to six O2- atoms to form distorted SrO6 pentagonal pyramids that share corners with four equivalent AsO4 tetrahedra, an edgeedge with one CoO6 octahedra, and an edgeedge with one SrO6 pentagonal pyramid. There are a spread of Sr–O bond distances ranging from 2.42–2.70 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent AsO4 tetrahedra, an edgeedge with one CoO6 octahedra, and an edgeedge with one SrO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 2.08–2.27 Å. In the second Co2+ site, Co2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Co–O bond distances ranging from 1.97–2.32 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.78–1.86 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CoO6 octahedra and corners with four equivalent SrO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 57–66°. There are a spread of As–O bond distances ranging from 1.72–1.74 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Co2+ and one O2- atom. The O–O bond length is 1.49 Å. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co2+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted tetrahedral geometry to one Sr2+, two Co2+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Co2+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Co2+, and one As5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one As5+, and one O2- atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Sr2+ and one As5+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1985

Results from the UCSD magnetic monopole search

The energy loss mechanism for slowly moving magnetic monopoles in helium provides a means of extending the search for such particles by ionization techniques to velocities approximately 3 X 1 million cm/sec (beta approximately equals 0.0001). Other gases (e.g., CH2 or CO2) mixed with helium will be ionized with high efficiency by collisions with excited helium atoms, thus allowing the use of large proportional chamber systems for the detection of the monopoles. The first reported results utilizing this mechanism was the experiment of Kajino, et al., using a detector with an area-solid angle product alpha time delta alpha of 24.7 square meters sr. They set a limit on the flux of monopoles of 7.2 x 10 to the 13th power cm(-2) sr(-1) sec(-1) at a 90% confidence level for beta 3x 0.0001. Here, the results of a He:CH2 proportional tube array designed to extend the velocity limit down to beta approximately 0.0001 are reported. The detector which has been operating at the University of California, San Diego (UCSD) since last summer, is a prototype for a larger array currently under construction at UCSD. The data presented here is from 200 days of live time with the prototype detector.

Masek, G. E.↗
NASA NTRS1991

Aerosol backscatter measurements at 10.6 microns with airborne and ground-based CO2 Doppler lidars over the Colorado High Plains. II - Backscatter structure

Measurements of tropospheric aerosol volume backscatter coefficients at 10.6-microns wavelength were obtained with airborne continuous wave and ground-based pulsed CO2 Doppler lidars over the Colorado High Plains during a 20-day period in summer 1982. A persistent 'background' layer was found between 6- and 10-km altitude, with a generally uniform backscatter mixing ratio of about 10 to the -10th sq m/kg per sr. The upper boundary of this background layer varied with the tropopause height; the lower boundary varied with the strength and diurnal cycle of convective mixing in the planetary boundary layer (PBL). For quiescent meteorological conditions, the transition from the PBL to the background layer was usually very sharp, with backscatter decreases sometimes as large as 3 decades in about 70 m. Sharp gradients were also found at the boundaries of shallow (tens of meters) subvisible cirrus clouds. For less stable conditions, associated with vertical aerosol transport by deep cumuliform clouds, backscatter tended to decrease exponentially with altitude.

Bowdle, David A.↗
DOE OSTI2020

Materials Data on SrMg30CoO32 by Materials Project

SrMg30CoO32 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.32 Å) and two longer (2.33 Å) Sr–O bond lengths. There are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent SrO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent CoO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.97 Å) and four longer (2.18 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent CoO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.09 Å) and four longer (2.15 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.12–2.15 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent SrO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.98 Å) and four longer (2.18 Å) Mg–O bond lengths. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one SrO6 octahedra, an edgeedge with one CoO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Mg–O bond distances ranging from 2.11–2.19 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.14–2.16 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CoO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Mg–O bond distances ranging from 2.13–2.16 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one SrO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Mg–O bond distances ranging from 2.10–2.20 Å. Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.12 Å) and two longer (2.22 Å) Co–O bond lengths. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded to five Mg2+ and one Co2+ atom to form OMg5Co octahedra that share corners with six OMg5Co octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg5Co octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the third O2- site, O2- is bonded to one Sr2+ and five Mg2+ atoms to form a mixture of edge and corner-sharing OSrMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the fourth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OMg5Co octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the fifth O2- site, O2- is bonded to five Mg2+ and one Co2+ atom to form a mixture of edge and corner-sharing OMg5Co octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the sixth O2- site, O2- is bonded to one Sr2+ and five Mg2+ atoms to form OSrMg5 octahedra that share corners with six OMg5Co octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. The O–Mg bond length is 1.97 Å. In the seventh O2- site, O2- is bonded to one Sr2+ and five Mg2+ atoms to form OSrMg5 octahedra that share corners with six OMg5Co octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of O–Mg bond distances ranging from 1.97–2.20 Å. In the eighth O2- site, O2- is bonded to six Mg2+ atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the ninth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OSrMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the tenth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OSrMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.11 Å) and two longer (2.15 Å) O–Mg bond lengths. In the eleventh O2- site, O2- is bonded to one Sr2+ and five Mg2+ atoms to form OSrMg5 octahedra that share corners with six OMg5Co octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. Both O–Mg bond lengths are 2.20 Å. In the twelfth O2- site, O2- is bonded to five Mg2+ and one Co2+ atom to form a mixture of edge and corner-sharing OMg5Co octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of O–Mg bond distances ranging from 2.11–2.18 Å. In the thirteenth O2- site, O2- is bonded to one Sr2+ and five Mg2+ atoms to form OSrMg5 octahedra that share corners with six OSrMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.19 Å) and two longer (2.20 Å) O–Mg bond lengths.

36 MATERIALS SCIENCE↗
NASA NTRS1999

Investigating the Martian Environment with the Mars Global Surveyor Thermal Emission Spectrometer

The Thermal Emission Spectrometer (TES) onboard Mars Global Surveyor (MGS) is being used to investigate the surface and atmosphere of Mars and the martian moons Phobos and Deimos. As such, it builds upon infrared observations obtained by previous spacecraft, e.g.. Mariner 9 and Viking Orbiters. The objectives of the TES experiment are: (1) determine and map surface minerals. rocks. and ices; (2) study the atmospheric dust composition. particle size, and spatial and temporal distribution; (3) investigate condensate clouds, CO2 and H2O, location. temperature, and height; (4) investigate polar cap deposits, e.g., growth, retreat, and energy balance; (5) measure the thermo-physical properties of surface materials; and (6) characterize the atmospheric structure and dynamics. The TES instrument is based upon a Michelson interferometer and collects data in the 1700-200 per cm region (about 6-50 micron at 5 or 10 per cm resolution. There are also broad-band bolometric (4.5100 microns and solar reflectance (0.3-2.7 microns) channels. The TES was designed to have a noise equivalent spectral radiance of 1.2 x l0(exp -8) per W per square cm per sr per cm corresponding to a signal-to-noise ratio of 490 at 1000 per cm (10 mm) for a 270 K scene and preflight data suggest a radiometric accuracy of about 1.2 x 10(exp -8) per W per square cm per sr per cm. In-flight observations indicate a small systematic calibration offset of about 1.2 x 10(exp -7) per W per square cm per sr per cm is present in the TES data. MGS achieved Mars orbital insertion September 11, 1997, and entered the initial aerobraking phase. MGS should have reached a circular orbit by early 1998. However, structural damage to one solar panel occurred during its deployment in the cruise phase and ultimately required an assessment of the extent of the damage and a much slower aerobraking period. This has delayed reaching the final circular orbit until March 1999. TES and the other MGS science instruments began operating just after orbital insertion and continued to obtain data until November 1998 when the TES was turned off to reduce power consumption on the spacecraft. TES data obtained during orbits 2 to 53 have previously been published and clearly illustrate the variety of scientific questions that can be addressed with them.

Roush, T. L.↗
NASA NTRS1988

Deccan volcanism at the Cretaceous-Tertiary boundary

The accuracy with which one can claim that Deccan trap volcanism occurred at the Cretaceous-Tertiary boundary (KTB) over a very short time interval is of key importance in deciding whether a volcanic origin of the KTB events should be taken seriously. In the two years since paleomagnetic, paleontological and geodynamic evidence was published, further data have become available and the case now appears to be well constrained. The Ar-40/Ar-39 results from six labs have yielded some 24 reliable plateau ages that narrow the age range to 65 to 69 Ma. Moreover, it appears that a significant part of this range results from inter-lab spread and possible minor alteration. Paleontology demonstrates that volcanism started in the Maestrichtian, more precisely in the A. mayaroensis zone. Paleomagnetism shows that volcanism spanned only 3 chrons and only one correlation remains possible, that of the main central reversed chron with 29R. Therefore, whereas Ar-40/Ar-39 is able only to restrict the duration of volcanism to some 4 Ma, paleomagnetism restricts it to 0.5 Ma. Using some geochemical indicators such as C-13 as proxy, it is suggested that volcanism actually consists of a few shorter events of unequal magnitude. Extrusion rates may be as high as 100 cu km/yr and fissure lengths as long as several 100 km. Such a scenario appears to be at least as successful as others in accounting for most anomalies observed at the KTB. Particularly important are Iridium and other platinum group elements (PGE) profiles, Sr-87/Sr-86, C-13, 0-18, other exotic geochemical signatures, spherules, soot, shocked minerals, selective and stepwise extinctions. The environmental impact of CO2 possibly released during explosive phases of volcanism, and SO2 released during effusive phases, and the ability of volcanism to ensure worldwide distribution of KTB products are now all addressed. In conclusion, the case for a causal link between internal hotspot activity, birth of the Reunion hotspot itself as the Deccan and KTB events appears to rest on an increasingly stronger basis.

Courtillot, V.↗
NASA NTRS1980

The thermal decomposition of 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) and RDXd6 at high temperatures

The ballistics behavior of nitramine propellants containing RDX in an inert binder was examined. It is shown that at 2000 to 5000 psi, depending on the particle size, a slope break or discontinuity in the log burning rate versus log pressure curve occurs. It is shown that at higher pressures the nitramine decomposition proceeds predominately by C-N bond rupture and gives CH2 and N20. At still higher pressures (after the slope break) the decomposition proceeds by N-N rupture. The decomposition of RDX was investigated from 170 to 800 C at atmospheric pressure. The major decomposition products were CH2, CO, CO2, N20, N2, and H20. The ratio of the products varied with the pyrolysis rate and temperature.

Miller, P. J.↗