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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Hg2PO4 by Materials Project

Hg2PO4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Hg+1.50+ sites. In the first Hg+1.50+ site, Hg+1.50+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.19 Å) and one longer (2.60 Å) Hg–O bond lengths. In the second Hg+1.50+ site, Hg+1.50+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Hg–O bond distances ranging from 2.26–2.49 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.54 Å) and two longer (1.57 Å) P–O bond length. In the second P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two Hg+1.50+ and one P5+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Hg+1.50+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Hg+1.50+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn2Hg2H3(SeO5)2 by Materials Project

Hg2Zn2H3(SeO5)2 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent Hg+1.50+ sites. In the first Hg+1.50+ site, Hg+1.50+ is bonded in a distorted linear geometry to two O2- atoms. There are one shorter (2.13 Å) and one longer (2.15 Å) Hg–O bond lengths. In the second Hg+1.50+ site, Hg+1.50+ is bonded in a 2-coordinate geometry to six O2- atoms. There are a spread of Hg–O bond distances ranging from 2.18–3.08 Å. Zn2+ is bonded to five O2- atoms to form ZnO5 trigonal bipyramids that share corners with three equivalent SeO4 tetrahedra and an edgeedge with one ZnO5 trigonal bipyramid. There are a spread of Zn–O bond distances ranging from 2.06–2.11 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted single-bond geometry to one H1+ and one O2- atom. The H–H bond length is 1.01 Å. The H–O bond length is 1.22 Å. In the second H1+ site, H1+ is bonded in a water-like geometry to two equivalent H1+ atoms. Se5+ is bonded to four O2- atoms to form SeO4 tetrahedra that share corners with three equivalent ZnO5 trigonal bipyramids. There are a spread of Se–O bond distances ranging from 1.68–1.72 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to two Hg+1.50+ and two equivalent Zn2+ atoms to form a mixture of edge and corner-sharing OZn2Hg2 tetrahedra. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Zn2+ and one Se5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Hg+1.50+, one Zn2+, and one Se5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Zn2+ and one Se5+ atom. In the fifth O2- site, O2- is bonded to two Hg+1.50+ and two equivalent Zn2+ atoms to form a mixture of edge and corner-sharing OZn2Hg2 tetrahedra. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Hg+1.50+, one H1+, and one Se5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HgO2 by Materials Project

HgO2 crystallizes in the orthorhombic Pbca space group. The structure is one-dimensional and consists of four HgO2 ribbons oriented in the (1, 0, 0) direction. Hg is bonded in a linear geometry to two equivalent O atoms. Both Hg–O bond lengths are 2.13 Å. O is bonded in a 2-coordinate geometry to one Hg and one O atom. The O–O bond length is 1.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg2NO4 by Materials Project

HgHgONO3 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of four nitric acid molecules and one HgHgO sheet oriented in the (1, 0, 0) direction. In the HgHgO sheet, there are two inequivalent Hg+1.50+ sites. In the first Hg+1.50+ site, Hg+1.50+ is bonded in a 2-coordinate geometry to two equivalent O2- atoms. Both Hg–O bond lengths are 2.11 Å. In the second Hg+1.50+ site, Hg+1.50+ is bonded in a 1-coordinate geometry to two equivalent O2- atoms. There are one shorter (2.20 Å) and one longer (3.02 Å) Hg–O bond lengths. O2- is bonded to four Hg+1.50+ atoms to form a mixture of distorted edge and corner-sharing OHg4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg4SbO6 by Materials Project

Hg4SbO6 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Hg4SbO6 sheet oriented in the (0, 0, 1) direction. there are four inequivalent Hg+1.75+ sites. In the first Hg+1.75+ site, Hg+1.75+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.27 Å) and one longer (2.28 Å) Hg–O bond lengths. In the second Hg+1.75+ site, Hg+1.75+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Hg–O bond distances ranging from 2.11–2.30 Å. In the third Hg+1.75+ site, Hg+1.75+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Hg–O bond distances ranging from 2.11–2.30 Å. In the fourth Hg+1.75+ site, Hg+1.75+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.27 Å) and one longer (2.28 Å) Hg–O bond lengths. Sb5+ is bonded in an octahedral geometry to six O2- atoms. There are two shorter (1.96 Å) and four longer (2.11 Å) Sb–O bond lengths. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Hg+1.75+ and one Sb5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Hg+1.75+ and one Sb5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Hg+1.75+ and one Sb5+ atom. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to two Hg+1.75+ and one Sb5+ atom. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to two Hg+1.75+ and one Sb5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Hg+1.75+ and one Sb5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba7Hg31 by Materials Project

Ba7Hg31 crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are four inequivalent Ba sites. In the first Ba site, Ba is bonded in a 8-coordinate geometry to fourteen Hg atoms. There are a spread of Ba–Hg bond distances ranging from 3.58–3.94 Å. In the second Ba site, Ba is bonded in a 8-coordinate geometry to eight Hg atoms. There are two shorter (3.57 Å) and six longer (3.68 Å) Ba–Hg bond lengths. In the third Ba site, Ba is bonded in a 2-coordinate geometry to sixteen Hg atoms. There are a spread of Ba–Hg bond distances ranging from 3.43–4.16 Å. In the fourth Ba site, Ba is bonded in a 12-coordinate geometry to fifteen Hg atoms. There are a spread of Ba–Hg bond distances ranging from 3.50–3.80 Å. There are seven inequivalent Hg sites. In the first Hg site, Hg is bonded in a 4-coordinate geometry to four Ba and two equivalent Hg atoms. Both Hg–Hg bond lengths are 2.97 Å. In the second Hg site, Hg is bonded in a 6-coordinate geometry to two equivalent Ba and six Hg atoms. There are a spread of Hg–Hg bond distances ranging from 3.05–3.32 Å. In the third Hg site, Hg is bonded in a 3-coordinate geometry to three Ba and seven Hg atoms. There are a spread of Hg–Hg bond distances ranging from 3.29–3.38 Å. In the fourth Hg site, Hg is bonded in a body-centered cubic geometry to four Ba and four Hg atoms. There are three shorter (2.97 Å) and one longer (3.01 Å) Hg–Hg bond lengths. In the fifth Hg site, Hg is bonded in a body-centered cubic geometry to four Ba and four Hg atoms. All Hg–Hg bond lengths are 3.04 Å. In the sixth Hg site, Hg is bonded in a 10-coordinate geometry to four Ba and six Hg atoms. In the seventh Hg site, Hg is bonded in a 4-coordinate geometry to three Ba and three Hg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Stannous chloride as a tool for mercury stripping in contaminated streams: Experimental assessment of toxicity in an invertebrate model species

In this work, the chronic toxicity of an innovative Hg water treatment system using tin (Sn) (II) chloride (SnCl 2 ) followed by air stripping was assessed through measurements of survival, growth, and reproduction rate in the freshwater cladoceran Ceriodaphnia dubia, a model species for toxicity testing. We first calculated the concentrations of Hg causing 25% reduction in survival and reproduction (Lethal or Inhibition Concentrations, or LC 25 and IC 25 , for survival and reproduction, respectively) through exposure to aqueous Hg at concentrations ranging from 0 to 25,000 ng L -1 . Then, we treated media (DMW and natural stream water) contaminated with Hg at LC 25 and IC 25 concentrations with SnCl 2 at a Sn:Hg stoichiometric ratio of 8:1 and air stripping and exposed C. dubia to this Sn-amended media. Our results showed that Hg significantly affected survival, reproduction rates and impaired growth. SnCl 2 -treatment removed 100% of the Hg from the media at all concentrations tested with no deleterious effects on survival, growth and reproduction. Our results confirmed the efficacy of SnCl 2 in removing aqueous Hg from stream water and showed that the added Sn did not impact C. dubia at the concentrations tested, supporting the suitability of SnCl 2 -based treatments in appropriate Hg-contaminated environments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Demethylation or Sorption? The Fate of Methylmercury in the Presence of Manganese Dioxide

Manganese oxide (MnO 2 ) amendments to mercury (Hg)-contaminated sediment have been shown to decrease methylmercury (MeHg) concentrations in sediment porewater. In the absence of solid-phase MeHg measurements, it is unclear whether the decreased porewater concentrations are due to inhibition of methylation, adsorption of the MeHg to the MnO 2 , demethylation of MeHg catalyzed by the MnO 2 , or some combination of these mechanisms. We conducted controlled laboratory experiments to determine whether MeHg losses from solution in the presence of amorphous MnO 2 are due to sorption or demethylation. In this work, we quantified MeHg in the dissolved phase and solid phase and found that no demethylation occurred. We used batch and isotherm experiments to determine MeHg sorption efficiency to MnO 2 in a variety of solutions with varying ionic strength and dissolved organic matter (DOM) concentration. Isotherms over an initial concentration range of 5–500 ng/L of MeHg showed no saturation effects. Increasing ionic strength from 0.012 M to 0.1 M produced relatively minor decreases in MeHg sorption. Increasing DOM concentrations from 0.64 to 16.4 mg C/L yielded substantial decreases in MeHg sorption. Under the experimental conditions, MnO2 is a less efficient MeHg sorbent compared to other sorbent materials, such as Thiol-SAMMS®, activated carbon, and biochar.

42 ENGINEERING↗
DOE OSTI2020

Materials Data on Hg by Materials Project

Hg crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of two mercury molecules. Hg is bonded in a 2-coordinate geometry to atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na5(Sn5Hg)2 by Materials Project

Na5(HgSn5)2 is Magnesium tetraboride-derived structured and crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. there are three inequivalent Na sites. In the first Na site, Na is bonded in a 2-coordinate geometry to two equivalent Hg and eight Sn atoms. Both Na–Hg bond lengths are 3.25 Å. There are a spread of Na–Sn bond distances ranging from 3.62–3.71 Å. In the second Na site, Na is bonded in a 7-coordinate geometry to one Hg and seven Sn atoms. The Na–Hg bond length is 3.25 Å. There are a spread of Na–Sn bond distances ranging from 3.26–3.73 Å. In the third Na site, Na is bonded in a 8-coordinate geometry to two equivalent Hg and six Sn atoms. There are one shorter (3.27 Å) and one longer (3.42 Å) Na–Hg bond lengths. There are a spread of Na–Sn bond distances ranging from 3.25–3.58 Å. Hg is bonded in a 8-coordinate geometry to four Na and four Sn atoms. There are a spread of Hg–Sn bond distances ranging from 2.91–3.13 Å. There are five inequivalent Sn sites. In the first Sn site, Sn is bonded in a 8-coordinate geometry to four Na, one Hg, and three Sn atoms. There are two shorter (2.93 Å) and one longer (3.06 Å) Sn–Sn bond lengths. In the second Sn site, Sn is bonded in a 7-coordinate geometry to three Na, one Hg, and three Sn atoms. There are one shorter (2.95 Å) and one longer (2.98 Å) Sn–Sn bond lengths. In the third Sn site, Sn is bonded in a 7-coordinate geometry to three Na and four Sn atoms. There are a spread of Sn–Sn bond distances ranging from 2.94–3.14 Å. In the fourth Sn site, Sn is bonded in a 7-coordinate geometry to three Na, one Hg, and three Sn atoms. The Sn–Sn bond length is 2.97 Å. In the fifth Sn site, Sn is bonded in a 8-coordinate geometry to four Na, one Hg, and three Sn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg3AsO5 by Materials Project

Hg3AsO5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Hg+1.67+ sites. In the first Hg+1.67+ site, Hg+1.67+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Hg–O bond distances ranging from 2.10–2.97 Å. In the second Hg+1.67+ site, Hg+1.67+ is bonded to six O2- atoms to form distorted HgO6 octahedra that share corners with four equivalent AsO4 tetrahedra and edges with two equivalent HgO6 octahedra. There are a spread of Hg–O bond distances ranging from 2.18–2.72 Å. In the third Hg+1.67+ site, Hg+1.67+ is bonded in a 1-coordinate geometry to one Hg+1.67+ and four O2- atoms. The Hg–Hg bond length is 2.62 Å. There are a spread of Hg–O bond distances ranging from 2.25–3.09 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent HgO6 octahedra. The corner-sharing octahedra tilt angles range from 53–64°. There are a spread of As–O bond distances ranging from 1.71–1.77 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Hg+1.67+ and one As5+ atom. In the second O2- site, O2- is bonded to four Hg+1.67+ atoms to form distorted edge-sharing OHg4 tetrahedra. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Hg+1.67+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Hg+1.67+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to three Hg+1.67+ and one As5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg3HN2O7 by Materials Project

Hg3N2HO7 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of two Hg3N2HO7 ribbons oriented in the (0, 1, 0) direction. there are three inequivalent Hg+1.67+ sites. In the first Hg+1.67+ site, Hg+1.67+ is bonded in a 1-coordinate geometry to one O2- atom. The Hg–O bond length is 2.18 Å. In the second Hg+1.67+ site, Hg+1.67+ is bonded in a 1-coordinate geometry to one Hg+1.67+ and five O2- atoms. The Hg–Hg bond length is 2.60 Å. There are a spread of Hg–O bond distances ranging from 2.33–2.95 Å. In the third Hg+1.67+ site, Hg+1.67+ is bonded in a distorted single-bond geometry to one Hg+1.67+ and one O2- atom. The Hg–O bond length is 2.22 Å. There are two inequivalent N4+ sites. In the first N4+ site, N4+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.24–1.31 Å. In the second N4+ site, N4+ is bonded in a trigonal planar geometry to three O2- atoms. All N–O bond lengths are 1.27 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one N4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Hg+1.67+ and one H1+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Hg+1.67+ and one N4+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one N4+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Hg+1.67+ and one N4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Hg+1.67+ and one N4+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one Hg+1.67+ and one N4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Optimizing CO 2 -Loaded Aqueous Amine Solutions for Higher Electrocatalytic CO 2 Reduction Activity

The activity of aqueous-based carbon dioxide reduction (CO 2 R) reactions is often limited by the solubility of CO 2 . The addition of amines can increase the total dissolved carbon in water through the formation of bicarbonate and carbamate species, which has been used to a great effect to capture CO 2 from dilute streams. Here, in this study, we explore the effect of 12 primary and secondary amines of varying Brønsted basicity, steric profile, and hydrogen-bonding capabilities on the aqueous CO 2 R to CO activity of a molecular Ni(cyclam)Cl 2 catalyst with a Hg electrode. Addition of some of the amines results in greater activity and selectivity for CO production compared to equivalent aqueous solutions without added amines. Under optimal conditions (0.4 M 3-amino-propionitrile), there is an over sevenfold increase in partial current density and greater selectivity for CO compared to equivalent conditions with no amine. Interestingly, the increase in activity did not correlate to any single property across the 12 amines. To elucidate the effect of the amine additives on catalysis, we used vapor–liquid equilibrium modeling (VLE), 13 C NMR spectroscopy, and computational analysis to determine the carbon speciation of the solutions. These results indicate that for amines without ethylalcohol functionalities, CO 2 R activity correlates with carbamate concentration, which is in turn governed by amine basicity and steric effects. However, this correlation does not persist for amines with ethylalcohol functionalities, which can form more stable carbamates through intramolecular-hydrogen bonding. These studies demonstrate that amine additives can enhance aqueous CO 2 R activity and selectivity and describe amine properties that lead to these higher performance metrics.

Amines↗
DOE OSTI2020

Materials Data on Zn2Hg2H3(SO5)2 by Materials Project

(HgZnSO5)4(H2)3 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional and consists of four molecular hydrogen molecules and one HgZnSO5 framework. In the HgZnSO5 framework, there are two inequivalent Hg+1.50+ sites. In the first Hg+1.50+ site, Hg+1.50+ is bonded in a 2-coordinate geometry to six O2- atoms. There are a spread of Hg–O bond distances ranging from 2.10–2.97 Å. In the second Hg+1.50+ site, Hg+1.50+ is bonded in a distorted linear geometry to two O2- atoms. There are one shorter (2.07 Å) and one longer (2.10 Å) Hg–O bond lengths. Zn2+ is bonded to five O2- atoms to form ZnO5 trigonal bipyramids that share corners with three equivalent SO4 tetrahedra and an edgeedge with one ZnO5 trigonal bipyramid. There are a spread of Zn–O bond distances ranging from 2.01–2.21 Å. S5+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with three equivalent ZnO5 trigonal bipyramids. There are a spread of S–O bond distances ranging from 1.46–1.52 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Hg+1.50+, one Zn2+, and one S5+ atom. In the second O2- site, O2- is bonded to two Hg+1.50+ and two equivalent Zn2+ atoms to form a mixture of corner and edge-sharing OZn2Hg2 tetrahedra. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Zn2+ and one S5+ atom. In the fourth O2- site, O2- is bonded to two Hg+1.50+ and two equivalent Zn2+ atoms to form a mixture of corner and edge-sharing OZn2Hg2 tetrahedra. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Zn2+ and one S5+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one Hg+1.50+ and one S5+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2017

The Use of Altered Gravity as a Tool to Understand Neurovestibular Mechanisms in Vertebrates

Vertebrates sense gravito-inertial acceleration by mechanoreceptors (hair cells) in the otolith structures of the inner ear. These structures consist of ciliated sensory hair cells surmounted by biomineral grains of calcium carbonate (CaCO3) called otoconia that provide mechanical loading of hair cell cilia. Changes in their high density can alter the hair cells sensitivity to acceleration and orientation with respect to gravity. A widely considered mechanism by which the animal responds to a chronic change in amplitude of gravity is a change in weight-lending otoconia. Hair cells are synaptically coupled to the vestibular nerve afferents that convey the signals into the brain. Synapses are modifiable in strength and numbers, and thereby can be an additional target to adjust the sensation as the gravity load changes. Here, we present the results obtained in 2 species exposed both to G and HG. Adult toadfish, Opsanus tau, were exposed to G in 2 short-duration shuttle missions and to 1.4 2.24G [resultant] centrifugation for 1-32 days; re-adaptation was studied following 1-8 days after return to 1G. Results show a biphasic pattern in response to 2.24G: initial hypersensitivity, similar to that observed after G exposure, followed by transition to a significant decrease at 16-32 days. Recovery from HG exposure is 4-8 days. Two major pieces of information are still needed: vertebrate hair cell response to altered gravity and impact of longer duration exposures on sensory plasticity. To address the latter we applied electron microscopic techniques to image otoconia mass obtained from 1) mice subjected to 91-days of weightlessness in the Mouse Drawer System (MDS) flown on International Space Station, 2) mice subjected to 91-days of 1.24G centrifugation on ground, and 3) mice flown on 2 short-duration orbital missions. Images indicate a clear restructuring of individual otoconia, suggesting deposition to the outer shell. Images from their HG counterparts indicate the converse - an ablation of the otoconia mass. For shorter duration exposures to weightlessness on 13-day shuttle missions mice otoconia appear normal. Despite the permanence of 1G in evolution the animal senses exposure to a novel, non-1G, environment and adaptive mechanisms are initiated - in the short term compensation is likely confined to the peripheral sensory receptors, the brain or both. For longer exposures structural modifications of the endorgan may also result.

vertebrate↗
DOE OSTI2020

Materials Data on K5Hg7 by Materials Project

K5Hg7 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are five inequivalent K sites. In the first K site, K is bonded in a 8-coordinate geometry to eight Hg atoms. There are a spread of K–Hg bond distances ranging from 3.56–3.85 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight Hg atoms. There are a spread of K–Hg bond distances ranging from 3.70–3.78 Å. In the third K site, K is bonded in a 2-coordinate geometry to eight Hg atoms. There are a spread of K–Hg bond distances ranging from 3.56–3.93 Å. In the fourth K site, K is bonded in a 8-coordinate geometry to twelve Hg atoms. There are a spread of K–Hg bond distances ranging from 3.70–4.06 Å. In the fifth K site, K is bonded in a 10-coordinate geometry to ten Hg atoms. There are a spread of K–Hg bond distances ranging from 3.58–3.81 Å. There are four inequivalent Hg sites. In the first Hg site, Hg is bonded in a 10-coordinate geometry to seven K and three Hg atoms. There are a spread of Hg–Hg bond distances ranging from 3.10–3.19 Å. In the second Hg site, Hg is bonded in a 10-coordinate geometry to eight K and two equivalent Hg atoms. Both Hg–Hg bond lengths are 3.33 Å. In the third Hg site, Hg is bonded in a 1-coordinate geometry to six K and three Hg atoms. There are one shorter (3.12 Å) and one longer (3.23 Å) Hg–Hg bond lengths. In the fourth Hg site, Hg is bonded in a 10-coordinate geometry to six K and four Hg atoms. The Hg–Hg bond length is 3.09 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr2Hg2O9 by Materials Project

Cr2Hg2O9 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of two Cr2Hg2O9 sheets oriented in the (0, 0, 1) direction. Cr is bonded in a tetrahedral geometry to four O atoms. There is two shorter (1.62 Å) and two longer (1.74 Å) Cr–O bond length. Hg is bonded in a 2-coordinate geometry to three O atoms. There are two shorter (2.09 Å) and one longer (2.54 Å) Hg–O bond lengths. There are five inequivalent O sites. In the first O site, O is bonded in an L-shaped geometry to two equivalent Hg atoms. In the second O site, O is bonded in a bent 120 degrees geometry to one Cr and one Hg atom. In the third O site, O is bonded in a single-bond geometry to one Cr atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one Cr and one Hg atom. In the fifth O site, O is bonded in a single-bond geometry to one Cr atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Comparing Trace Element Bioaccumulation and Depuration in Snails and Mayfly Nymphs at a Coal Ash–Contaminated Site

In this work, we examined the bioaccumulation of essential (Cu, Fe, Se, and Zn) and nonessential (As and Hg) trace elements in 2 aquatic invertebrate species (adult snails and mayfly nymphs) with different feeding habits at the site of a coal ash spill. Differences in food web pathway, exposure concentrations, and biological processing affected bioaccumulation patterns in these species. Mayflies had higher body burdens, but snails had higher retention of most elements studied.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗