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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on LiAlS3(Cl2O3)2 by Materials Project

Li(SO2)3AlCl4 crystallizes in the orthorhombic Pnma space group. The structure is one-dimensional and consists of four AlCl4 clusters and two Li(SO2)3 ribbons oriented in the (1, 0, 0) direction. In each AlCl4 cluster, Al3+ is bonded in a tetrahedral geometry to four Cl1- atoms. There are a spread of Al–Cl bond distances ranging from 2.15–2.18 Å. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Al3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Al3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Al3+ atom. In each Li(SO2)3 ribbon, Li1+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.13–2.20 Å. There are two inequivalent S4+ sites. In the first S4+ site, S4+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the second S4+ site, S4+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S4+ atom. In the third O2- site, O2- is bonded in a linear geometry to one Li1+ and one S4+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsC2S2N(O2F3)2 by Materials Project

(Cs(SO2)2)2N2(CF3)4 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of eight ammonia molecules; sixteen fluoroform molecules; and two Cs(SO2)2 sheets oriented in the (1, 0, 0) direction. In each Cs(SO2)2 sheet, Cs1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Cs–O bond distances ranging from 3.13–3.36 Å. There are two inequivalent S2+ sites. In the first S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the second S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to two equivalent Cs1+ and one S2+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Cs1+ and one S2+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to two equivalent Cs1+ and one S2+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Cs1+ and one S2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Materials Data on KC2S2N(O2F3)2 by Materials Project

(K(SO2)2)2N2(CF3)4 crystallizes in the orthorhombic Pbcn space group. The structure is two-dimensional and consists of sixteen ammonia molecules; thirty-two fluoroform molecules; and two K(SO2)2 sheets oriented in the (0, 0, 1) direction. In each K(SO2)2 sheet, there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.76–3.06 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.83–3.40 Å. There are four inequivalent S2+ sites. In the first S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the second S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the third S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the fourth S2+ site, S2+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S2+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S2+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S2+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S2+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to two K1+ and one S2+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S2+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S2+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaB6S4(Br3O4)2 by Materials Project

Na(SO2)4(BBr)6 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of twenty-four bromoborane molecules and two Na(SO2)4 ribbons oriented in the (0, 0, 1) direction. In each Na(SO2)4 ribbon, Na1+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–2.91 Å. There are four inequivalent S+0.75- sites. In the first S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the second S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.45 Å) and one longer (1.46 Å) S–O bond length. In the third S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the fourth S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+ and one S+0.75- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S+0.75- atom. In the third O2- site, O2- is bonded in a distorted linear geometry to one Na1+ and one S+0.75- atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S+0.75- atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and one S+0.75- atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one S+0.75- atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and one S+0.75- atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one S+0.75- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiB6S4(Cl3O4)2 by Materials Project

Li(SO2)4(BCl)6 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of twelve chloroborane molecules and one Li(SO2)4 cluster. In the Li(SO2)4 cluster, Li1+ is bonded in a trigonal bipyramidal geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 2.03–2.28 Å. There are four inequivalent S+0.75+ sites. In the first S+0.75+ site, S+0.75+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the second S+0.75+ site, S+0.75+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.45 Å) and one longer (1.46 Å) S–O bond length. In the third S+0.75+ site, S+0.75+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. In the fourth S+0.75+ site, S+0.75+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Li1+ and one S+0.75+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S+0.75+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S+0.75+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one S+0.75+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S+0.75+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one S+0.75+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S+0.75+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one S+0.75+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaCuH28CS6(N2O7)2 by Materials Project

NaCuCH8(SO2)6(NH4)4(H2O)2 crystallizes in the monoclinic Pc space group. The structure is one-dimensional and consists of eight ammonium molecules; four water molecules; and two NaCuCH8(SO2)6 ribbons oriented in the (1, 0, 1) direction. In each NaCuCH8(SO2)6 ribbon, Na1+ is bonded to six O2- atoms to form distorted NaO6 pentagonal pyramids that share a cornercorner with one CH3O tetrahedra. There are a spread of Na–O bond distances ranging from 2.33–2.61 Å. Cu3+ is bonded in a trigonal planar geometry to three S2- atoms. There are one shorter (2.20 Å) and two longer (2.21 Å) Cu–S bond lengths. C4+ is bonded to three H1+ and one O2- atom to form CH3O tetrahedra that share a cornercorner with one NaO6 pentagonal pyramid. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. The C–O bond length is 1.43 Å. There are eight inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C4+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C4+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C4+ atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted single-bond geometry to one Cu3+ and one S2- atom. The S–S bond length is 2.07 Å. In the second S2- site, S2- is bonded in a distorted water-like geometry to one Cu3+ and one S2- atom. The S–S bond length is 2.06 Å. In the third S2- site, S2- is bonded in a distorted single-bond geometry to one Cu3+ and one S2- atom. The S–S bond length is 2.05 Å. In the fourth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one S2- and three O2- atoms. There are a spread of S–O bond distances ranging from 1.48–1.50 Å. In the fifth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one S2- and three O2- atoms. There is one shorter (1.47 Å) and two longer (1.50 Å) S–O bond length. In the sixth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one S2- and three O2- atoms. There is one shorter (1.48 Å) and two longer (1.50 Å) S–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the third O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S2- atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+ and one S2- atom. In the ninth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and one S2- atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one C4+, and one H1+ atom. In the eleventh O2- site, O2- is bonded in a water-like geometry to one Na1+ and two H1+ atoms. In the twelfth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and two H1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NiH20C12S2(NO4)2 by Materials Project

NiC4H4(SO2)2(C3NH6)2(CO)2(H2O)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four formaldehyde molecules, four trimethylamine molecules, four water molecules, and two NiC4H4(SO2)2 clusters. In each NiC4H4(SO2)2 cluster, Ni2+ is bonded in an octahedral geometry to two equivalent S2- and four O2- atoms. Both Ni–S bond lengths are 2.49 Å. There are two shorter (2.13 Å) and two longer (2.15 Å) Ni–O bond lengths. There are two inequivalent C+0.33+ sites. In the first C+0.33+ site, C+0.33+ is bonded in a single-bond geometry to one S2- atom. The C–S bond length is 1.67 Å. In the second C+0.33+ site, C+0.33+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.27 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. S2- is bonded in an L-shaped geometry to one Ni2+ and one C+0.33+ atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Ni2+ and one C+0.33+ atom. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Ni2+ and two H1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Materials Data on NaB6S4(I3O4)2 by Materials Project

Na(SO2)4(BI)6 crystallizes in the orthorhombic Pnma space group. The structure is one-dimensional and consists of forty-eight iodoborane molecules and two Na(SO2)4 ribbons oriented in the (0, 0, 1) direction. In each Na(SO2)4 ribbon, Na1+ is bonded in a distorted pentagonal pyramidal geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.45–2.61 Å. There are five inequivalent S+0.75- sites. In the first S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.45 Å) and one longer (1.46 Å) S–O bond length. In the second S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.46 Å. In the third S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both S–O bond lengths are 1.46 Å. In the fourth S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both S–O bond lengths are 1.46 Å. In the fifth S+0.75- site, S+0.75- is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.45 Å) and one longer (1.46 Å) S–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and one S+0.75- atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S+0.75- atom. In the third O2- site, O2- is bonded in a single-bond geometry to one S+0.75- atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Na1+ and one S+0.75- atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S+0.75- atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S+0.75- atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one S+0.75- atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S+0.75- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaB24S6(Br2O)12 by Materials Project

Na(SO2)6(BBr)24 crystallizes in the trigonal P-31c space group. The structure is zero-dimensional and consists of forty-eight bromoborane molecules and two Na(SO2)6 clusters. In each Na(SO2)6 cluster, Na1+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.44 Å. S+1.17- is bonded in a bent 120 degrees geometry to two O2- atoms. Both S–O bond lengths are 1.45 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S+1.17- atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and one S+1.17- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A global anthropogenic emission inventory of atmospheric pollutants from sector- and fuel-specific sources (1970–2017): an application of the Community Emissions Data System (CEDS)

Global anthropogenic emission inventories remain vital for understanding the sources of atmospheric pollution and the associated impacts on the environment, human health, and society. Rapid changes in today's society require that these inventories provide contemporary estimates of multiple atmospheric pollutants with both source sector and fuel type information to understand and effectively mitigate future impacts. To fill this need, we have updated the open-source Community Emissions Data System (CEDS) (Hoesly et al., 2019) to develop a new global emission inventory, CEDSGBD-MAPS. This inventory includes emissions of seven key atmospheric pollutants (NOx; CO; SO2; NH3; non-methane volatile organic compounds, NMVOCs; black carbon, BC; organic carbon, OC) over the time period from 1970–2017 and reports annual country-total emissions as a function of 11 anthropogenic sectors (agriculture; energy generation; industrial processes; on-road and non-road transportation; separate residential, commercial, and other sectors (RCO); waste; solvent use; and international shipping) and four fuel categories (total coal, solid biofuel, the sum of liquid-fuel and natural-gas combustion, and remaining process-level emissions). The CEDSGBD-MAPS inventory additionally includes monthly global gridded (0.5°?×?0.5°) emission fluxes for each compound, sector, and fuel type to facilitate their use in earth system models. CEDSGBD-MAPS utilizes updated activity data, updates to the core CEDS default scaling procedure, and modifications to the final procedures for emissions gridding and aggregation. Relative to the previous CEDS inventory (Hoesly et al., 2018), these updates extend the emission estimates from 2014 to 2017 and improve the overall agreement between CEDS and two widely used global bottom-up emission inventories. The CEDSGBD-MAPS inventory provides the most contemporary global emission estimates to date for these key atmospheric pollutants and is the first to provide global estimates for these species as a function of multiple fuel types and source sectors. Dominant sources of global NOx and SO2 emissions in 2017 include the combustion of oil, gas, and coal in the energy and industry sectors as well as on-road transportation and international shipping for NOx. Dominant sources of global CO emissions in 2017 include on-road transportation and residential biofuel combustion. Dominant global sources of carbonaceous aerosol in 2017 include residential biofuel combustion, on-road transportation (BC only), and emissions from the waste sector. Global emissions of NOx, SO2, CO, BC, and OC all peak in 2012 or earlier, with more recent emission reductions driven by large changes in emissions from China, North America, and Europe. In contrast, global emissions of NH3 and NMVOCs continuously increase between 1970 and 2017, with agriculture as a major source of global NH3 emissions and solvent use, energy, residential, and the on-road transport sectors as major sources of global NMVOCs. Due to similar development methods and underlying datasets, the CEDSGBD-MAPS emissions are expected to have consistent sources of uncertainty as other bottom-up inventories. The CEDSGBD-MAPS source code is publicly available online through GitHub: https://github.com/emcduffie/CEDS/tree/CEDS_GBD-MAPS (last access: 1 December 2020). The CEDSGBD-MAPS emission inventory dataset (both annual country-total and monthly global gridded files) is publicly available under https://doi.org/10.5281/zenodo.3754964 (McDuffie et al., 2020c).

Mcduffie, Erin↗
NASA NTRS1975

Radio detection of interstellar sulfur dioxide

Interstellar sulfur dioxide (SO2) has been detected in emission from the direction of the Orion Nebula molecular cloud and from Sgr B2. SO2 is the heaviest interstellar molecule detected to date, and the only nonlinear triatomic molecule which does not contain hydrogen. The remarkable Orion emission profiles suggest that two components are supporting the SO2 emission: a dense circumstellar-type envelope, which may be in maser emission, and a warm galactic cloud component.

Snyder, L. E.↗
NASA NTRS1978

Stratospheric aerosols and climatic change

Stratospht1ic sulfuric acid particles scatter and absorb sunlight and they scatter, absorb and emit terrestrial thermal radiation. These interactions play a role in the earth's radiation balance and therefore affect climate. The stratospheric aerosols are perturbed by volcanic injection of SO2 and ash, by aircraft injection of SO2, by rocket exhaust of Al2O3 and by tropospheric mixing of particles and pollutant SO2 and COS. In order to assess the effects of these perturbations on climate, the effects of the aerosols on the radiation balance must be understood and in order to understand the radiation effects the properties of the aerosols must be known. The discussion covers the aerosols' effect on the radiation balance. It is shown that the aerosol size distribution controls whether the aerosols will tend to warm or cool the earth's surface. Calculations of aerosol properties, including size distribution, for various perturbation sources are carried out on the basis of an aerosol model. Calculations are also presented of the climatic impact of perturbed aerosols due to volcanic eruptions and Space Shuttle flights.

Toon, O. B.↗
NASA NTRS1979

Io's surface and environs - A magmatic-volatile model

A model is proposed to account for the observed properties of Io. The crust is probably siliceous, but the outermost visible surface is composed primarily of several allotropes of elemental sulfur, plus frosts of SO2, H2S, and S2O. The 4-micron feature in Io's IR reflectance is identified as the (nu 1 + nu 3) band of SO2 frost. A possible source of the S is dissociation of iron sulfide brought up from the core by mantle convection. The SO2 is produced in the volcanoes, and the H2S by interaction of magnetospheric protons with the surface S. Delayed luminescence from S2O could cause the posteclipse brightening. The orbital torus is sustained by evaporation from molten ejecta from the volcanoes. Several additional diagnostic absorption bands and two additional minor torus species are predicted by this model.

Hapke, B.↗
NASA NTRS1979

Heterogeneous phase reactions of Martian volatiles with putative regolith minerals

The chemical reactivity of several minerals thought to be present in Martian fines is tested with respect to gases known in the Martian atmosphere. In these experiments, liquid water is excluded from the system, environmental temperatures are maintained below 0 C, and the solar illumination spectrum is stimulated in the visible and UV using a xenon arc lamp. Reactions are detected by mass spectrometric analysis of the gas phase over solid samples. No reactions were detected for Mars nominal gas over sulfates, nitrates, chloride, nontronite clay, or magnetite. Oxidation was not observed for basaltic glass, nontronite, and magnetite. However, experiments incorporating SO2 gas an expected product of volcanism and intrusive volatile release - gave positive results. Displacement of CO2 by SO2 occurred in all four carbonates tested. These reactions are catalyzed by irradiation with the solar simulator. A calcium nitrate hydrate released NO2 in the presence of SO2. These results have implications for the cycling of atmospheric CO2, H2O, and N2 through the regolith.

Clark, B. C.↗
NASA NTRS1980

Synergistic effects in trace gas-aerosol interactions

The reaction of SO2 and NO2 with soot has been studied experimentally by gravimetric determination of chemisorption with subsequent analysis of the chemisorbed species by various techniques. When samples of commercially available carbon black (used as soot surrogate) are exposed to SO2 or NO2 in dry air or N2 as carrier gas, no quantitative chemisorption (less than 5 micrograms per mg of substrate) is observed. However, exposure of the same grade of carbon to a combination of SO2 and NO2 in dry air of N2 results in significant chemisorption (180-200 micrograms/mg), a major fraction of which is analyzed as sulfate.

Schryer, D. R.↗
NASA NTRS1981

Evolution of the atmosphere of Venus

The photochemistry of the stratosphere of Venus was modeled using an updated and expanded chemical scheme, and the results of recent laboratory studies. The model satisfactorily accounts for the observations of CO, O2, (1) and SO2 in the stratosphere. Oxygen, derived from CO2 photolysis, is primarily consumed by CO2 recombination and oxidation of SO2 to H2SO4. Photolysis of HCl in the upper stratosphere provides a major source of odd hydrogen radicals essential for the catalytic oxidation of CO. Oxidation of SO2 by O occurs in the lower stratosphere, with the O-O bond broken by S + O2 and SO + HO2. The sensitivity of stratospheric chemistry to ambient H2 abundance was studied and the model prefers the high value (1 10 ppm) recently inferred from the Pioneer Venus ionospheric measurements. The importance of the photochemical production of S2O, (SO)2, S2, H2S2O2 and H2S2O3 is speculated. A number of previously unsuspected similarities between the chemistry of the stratospheres of Venus and the Earth, presented and discussed.

Yung, Y. L.↗
NASA NTRS1980

Io - Longtudinal distribution of sulfur dioxide frost

A longitudinal variation in the distribution of SO2 frost on Io is examined. Twenty spectra of Io (0.26 to 0.33 micrometer) are presented and a strong ultraviolet absorption is found shortward of 0.33 micrometer. The abundance of frost is greatest at orbital longitudes 72 to 137 degrees. Longitudes 250 to 323 degrees are least abundant in SO2. Comparisons are made with a Voyager color relief map, which suggest that SO2 frost is in greatest concentration in the white areas of Io and other sulfurous materials are in greatest concentration in the red areas.

Nelson, R. M.↗
NASA NTRS1980

Spectrophotometry of Io - Preliminary Voyager 1 results

Multispectral images of Io acquired with the Voyager 1 narrow-angle camera agree with earth-based spectrophotometry to better than 10%. Although the surface materials have general spectral properties similar to various allotropes of sulfur, their ultraviolet (UV) reflectances are much higher. It is likely that varying amounts of SO2 frost mixed with or absorbed on sulfur-rich materials raises the UV reflectance. The possible association with large amounts of SO2 with low temperature forms of sulfur in the white patches on Io is consistent with Io surface models in which SO2 and S exist in thermally stable stratified zones.

Soderblom, L.↗