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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaHg3 by Materials Project

NaHg3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Na is bonded in a body-centered cubic geometry to fourteen Hg atoms. There are eight shorter (3.24 Å) and six longer (3.74 Å) Na–Hg bond lengths. There are two inequivalent Hg sites. In the first Hg site, Hg is bonded to four equivalent Na and four equivalent Hg atoms to form a mixture of distorted edge, face, and corner-sharing HgNa4Hg4 tetrahedra. All Hg–Hg bond lengths are 3.24 Å. In the second Hg site, Hg is bonded in a distorted body-centered cubic geometry to six equivalent Na and eight equivalent Hg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd2Hg2H(SeO5)2 by Materials Project

Hg2Cd2H(SeO5)2 crystallizes in the monoclinic P2/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 6-coordinate geometry to six O2- atoms. There are a spread of Hg–O bond distances ranging from 2.13–2.69 Å. 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 2.08–3.05 Å. Cd2+ is bonded in a 5-coordinate geometry to one H1+ and five O2- atoms. The Cd–H bond length is 2.49 Å. There are a spread of Cd–O bond distances ranging from 2.23–2.38 Å. H1+ is bonded in a distorted bent 120 degrees geometry to two equivalent Cd2+ atoms. Se6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Se–O bond distances ranging from 1.66–1.70 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cd2+ and one Se6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Hg+1.50+, one Cd2+, and one Se6+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Hg+1.50+, one Cd2+, and one Se6+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two Hg+1.50+ and one Se6+ atom. In the fifth O2- site, O2- is bonded to two Hg+1.50+ and two equivalent Cd2+ atoms to form a mixture of edge and corner-sharing OCd2Hg2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaHg3 by Materials Project

LaHg3 crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. La is bonded in a 6-coordinate geometry to six equivalent Hg atoms. All La–Hg bond lengths are 3.26 Å. There are two inequivalent Hg sites. In the first Hg site, Hg is bonded to six equivalent Hg atoms to form distorted edge-sharing HgHg6 pentagonal pyramids. All Hg–Hg bond lengths are 3.07 Å. In the second Hg site, Hg is bonded in a 6-coordinate geometry to three equivalent La and three equivalent Hg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti3ZnHg4 by Materials Project

Ti3Hg4Zn is Tetraauricupride-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight Hg atoms. All Ti–Hg bond lengths are 2.95 Å. In the second Ti site, Ti is bonded in a distorted body-centered cubic geometry to eight equivalent Hg atoms. All Ti–Hg bond lengths are 2.96 Å. There are two inequivalent Hg sites. In the first Hg site, Hg is bonded in a distorted body-centered cubic geometry to four equivalent Ti and four equivalent Zn atoms. All Hg–Zn bond lengths are 2.94 Å. In the second Hg site, Hg is bonded in a distorted body-centered cubic geometry to eight Ti atoms. Zn is bonded in a distorted body-centered cubic geometry to eight equivalent Hg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(SnHg)2 by Materials Project

Sr(HgSn)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Sr is bonded in a 12-coordinate geometry to seven Hg and seven Sn atoms. There are a spread of Sr–Hg bond distances ranging from 3.50–3.92 Å. There are a spread of Sr–Sn bond distances ranging from 3.58–3.79 Å. There are two inequivalent Hg sites. In the first Hg site, Hg is bonded in a 8-coordinate geometry to four equivalent Sr and four Sn atoms. There are a spread of Hg–Sn bond distances ranging from 2.92–3.21 Å. In the second Hg site, Hg is bonded in a 7-coordinate geometry to three equivalent Sr and four Sn atoms. There are a spread of Hg–Sn bond distances ranging from 2.91–3.26 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 8-coordinate geometry to three equivalent Sr, four Hg, and one Sn atom. The Sn–Sn bond length is 2.92 Å. In the second Sn site, Sn is bonded in a 9-coordinate geometry to four equivalent Sr, four Hg, and one Sn atom. The Sn–Sn bond length is 2.95 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li6Ca17Hg9 by Materials Project

Li6Ca17Hg9 crystallizes in the cubic Im-3m space group. The structure is three-dimensional. Li is bonded in a 3-coordinate geometry to one Ca and three Hg atoms. The Li–Ca bond length is 3.38 Å. There are two shorter (2.79 Å) and one longer (3.12 Å) Li–Hg bond lengths. There are four inequivalent Ca sites. In the first Ca site, Ca is bonded in a distorted square co-planar geometry to two equivalent Ca and four equivalent Hg atoms. Both Ca–Ca bond lengths are 3.92 Å. All Ca–Hg bond lengths are 3.31 Å. In the second Ca site, Ca is bonded to twelve Ca atoms to form distorted corner-sharing CaCa12 cuboctahedra. All Ca–Ca bond lengths are 4.02 Å. In the third Ca site, Ca is bonded in a 4-coordinate geometry to one Ca and four Hg atoms. There are a spread of Ca–Hg bond distances ranging from 3.17–3.30 Å. In the fourth Ca site, Ca is bonded in a cuboctahedral geometry to twelve equivalent Li atoms. There are two inequivalent Hg sites. In the first Hg site, Hg is bonded in a 8-coordinate geometry to four equivalent Li and four equivalent Ca atoms. In the second Hg site, Hg is bonded in a 9-coordinate geometry to one Li and eight Ca atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CdHg3 by Materials Project

Hg3Cd crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Hg sites. In the first Hg site, Hg is bonded in a 8-coordinate geometry to four equivalent Hg and four equivalent Cd atoms. All Hg–Hg bond lengths are 3.29 Å. All Hg–Cd bond lengths are 3.47 Å. In the second Hg site, Hg is bonded in a square co-planar geometry to four equivalent Cd atoms. All Hg–Cd bond lengths are 3.29 Å. Cd is bonded to twelve Hg atoms to form a mixture of distorted face, edge, and corner-sharing CdHg12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg4SbO6 by Materials Project

Hg4SbO6 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of two Hg4SbO6 sheets oriented in the (0, 1, 0) direction. there are two inequivalent Hg+1.75+ sites. In the first 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 second Hg+1.75+ site, Hg+1.75+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.26 Å) and one longer (2.27 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 four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Hg+1.75+ and one Sb5+ atom. In the second O2- site, O2- is bonded in a trigonal planar geometry to two Hg+1.75+ and one Sb5+ atom. In the third O2- site, O2- is bonded in a trigonal planar geometry to two Hg+1.75+ and one Sb5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Hg+1.75+ and one Sb5+ atom.

36 MATERIALS SCIENCE↗
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↗
DOE OSTI2025

Plant genotype and rhizobia strain combinations strongly influence the transcriptome under heavy metal stress conditions in Medicago truncatula

Heavy metals such as cadmium (Cd) and mercury (Hg) pose significant threats to plant health and food safety as they are absorbed from the environment. Legumes are generally considered sensitive to heavy metals but possess standing genetic variation for accumulation and tolerance to toxic ions. We conducted a transcriptomic analysis on hydroponically and soil grown Medicago truncatula plants to investigate gene expression responses to Cd and Hg exposure in roots, leaves, and nodules. By using plant genotypes with varying metal tolerance or accumulation levels, we observed distinct clustering of gene ontologies, indicating tissue-specific, genotype-specific, and metal-specific gene expression patterns. Considering the symbiotic relationship between legumes and nitrogen-fixing bacteria, we further examined plant phenotypes and transcriptomes of plant genotypes with contrasting Hg accumulation levels and inoculated them with high or low Hg-tolerant Sinorhizobium medicae strains that have presence-absence variation for a mercury reductase (Mer) operon. Host plants inoculated with the Hg-tolerant rhizobia strain possessing a Mer operon exhibited less reduction in nodule number and plant biomass. A smaller reduction in iron (Fe) distribution in nodules after Hg stress was measured using X-ray Fluorescence (XRF) imaging. Dual transcriptome (host plant and bacteria) analysis of nodules revealed a remarkable decrease in the number of differentially expressed genes (DEGs) and clustering of gene ontologies in plants inoculated with the Hg-tolerant rhizobia strain, including symbiosis related genes. This finding suggests that the Hg-tolerant rhizobia strain has the potential to mitigate Hg stress in host plants. Furthermore, we observed genotype by-genotype interactions between the high Hg accumulating plant genotype and the Hg-tolerant rhizobia strain. These findings provide insights into enhancing plant resilience in contaminated environments through optimizing legume-rhizobia interactions for heavy metal tolerance.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Diel mercury concentration variations in a mercury-impacted stream

Here, filtered and particulate mercury (Hg) and methylmercury (MMHg), and associated water chemistry parameters, were evaluated bi-hourly for several 30 h periods during the summer and winter seasons at several distinct locations (downstream forested, midstream urban/suburban, upstream industrial) along a creek contaminated with high levels of inorganic Hg to determine if biogeochemical Hg and MMHg cycles respond to the daily photocycle. In summer particulate Hg and MMHg concentrations doubled overnight (excluding the upstream industrial site) concurrent with increases in turbidity and total suspended sediment; no such pattern was evident in winter. Seasonal and diel changes in the activity of macrobiota affecting the suspension of contaminated sediments are likely responsible for these patterns as other potential explanatory variables (e.g., instrument drift, pH, discharge) could not account for the range and timing of our observations. Diel patterns in filtered Hg (Hg D ) were significant only at locations and times of the year when channel shading was not present and daytime concentrations increased 22–89% above nighttime minima likely caused by direct and indirect photochemical reactions. Relationships between Hg D and dissolved organic carbon (DOC) concentration or character were inconsistent between sites. Unlike Hg D , there were significant diel patterns in filtered MMHg (MMHg D ) at all sites and times of year, with summer concentrations peaking in mid to late afternoon while the timing differed in winter, with concentrations peaking after sunset. Daily variability in MMHg D concentration ranged between 25 and 75%. The results imply key controls on net methylation occur within the stream or on the stream bed and include factors such as small-scale temperature changes in the water column and photosynthetic activity of stream biofilm. With respect to stream monitoring, results from this study indicate (1) consistent timing in stream Hg and MMHg sampling is required for accurate assessment of long-term trends, (2) in situ measurements of turbidity can be used to quantify diel dynamics of both particulate Hg and MMHg concentrations, and (3) in situ fluorescing dissolved organic matter (FDOM), a potential proxy for DOC, was not capable of resolving diel dynamics of filtered Hg or MMHg.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Tank 50 Simulant Grout and Toxicity Characteristic Leaching Procedure (TCLP) Results for Methyl Mercury Waste Acceptance Criteria (WAC) Limit

Testing of simulated Tank 50 salt solution grout, spiked with methyl mercury (MeHg) and ionic mercury, used the Toxicity Characteristic Leaching Procedure (TCLP) to evaluate leaching performance with respect to Hg and the Waste Acceptance Criteria (WAC) limits for the Saltstone Production Facility (SPF). This report describes the test parameters for simulant preparation and confirmatory analysis, grout preparation, TCLP leach testing and subsequent leachate analyses. These scoping tests were designed to provide an initial evaluation of the effect of increased MeHg and ionic Hg on the TCLP and were requested by Savannah River Remediation LLC (SRR) through a Technical Assistance Request (TAR). It is expected that this preliminary testing will likely lead to future, more detailed, testing involving the mercury (Hg) WAC and Hg limits with respect to the Tank 50 TCLP for mercury. The TCLP concentrations for total Hg have approached 0.06 mg/L in recent years for Tank 50 radioactive solutions containing up to 105 mg/L of Hg in the form of ionic (Hg(I/II), elemental (Hg(0)) and organo-mercury such as MeHg. In discussions with SRR personnel, it was decided for this non-baseline work to target Hg spike concentrations, using predominately MeHg, in the range of 150 to 350 mg/L total Hg to investigate corresponding Hg TCLP leaching behaviors.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Nutrient Exposure Alters Microbial Composition, Structure, and Mercury Methylating Activity in Periphyton in a Contaminated Watershed

The conversion of mercury (Hg) to monomethylmercury (MMHg) is a critical area of concern in global Hg cycling. Periphyton biofilms may harbor significant amounts of MMHg but little is known about the Hg-methylating potential of the periphyton microbiome. Therefore, we used high-throughput amplicon sequencing of the 16S rRNA gene, ITS2 region, and Hg methylation gene pair (hgcAB) to characterize the archaea/bacteria, fungi, and Hg-methylating microorganisms in periphyton communities grown in a contaminated watershed in East Tennes(see United States). Furthermore, we examined how nutrient amendments (nitrate and/or phosphate) altered periphyton community structure and function. We found that bacterial/archaeal richness in experimental conditions decreased in summer and increased in autumn relative to control treatments, while fungal diversity generally increased in summer and decreased in autumn relative to control treatments. Interestingly, the Hg-methylating communities were dominated by Proteobacteria followed by Candidatus Atribacteria across both seasons. Surprisingly, Hg methylation potential correlated with numerous bacterial families that do not contain hgcAB, suggesting that the overall microbiome structure of periphyton communities influences rates of Hg transformation within these microbial mats. To further explore these complex community interactions, we performed a microbial network analysis and found that the nitrate-amended treatment resulted in the highest number of hub taxa that also corresponded with enhanced Hg methylation potential. This work provides insight into community interactions within the periphyton microbiome that may contribute to Hg cycling and will inform future research that will focus on establishing mixed microbial consortia to uncover mechanisms driving shifts in Hg cycling within periphyton habitats.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Fungal necromass presents a high potential for Mercury immobilization in soil

Past industrial activities have generated many contaminated lands from which Mercury (Hg) escapes, primarily by volatilization. Current phytomanagement techniques aim to limit Hg dispersion by increasing its stabilization in soil. Although soil fungi represent a source of Hg emission associated with biovolatilization mechanisms, there is limited knowledge about how dead fungal residues (i.e., fungal necromass) interact with soil Hg. This study determined the Hg biosorption potential of fungal necromass and the chemical drivers of passive Hg binding with dead mycelia. Fungal necromass was incubated under field conditions with contrasting chemical properties at a well-characterized Hg phytomanagement experimental site in France. After four months of incubation in soil, fungal residues passively accumulated substantial quantities of Hg in their recalcitrant fractions ranging from 400 to 4500 μg Hg/kg. In addition, infrared spectroscopy revealed that lipid compounds explained the amount of Hg biosorption to fungal necromass. In conclusion, based on these findings, we propose that fungal necromass is likely an important factor in Hg immobilization in soil.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Materials Data on Na3Hg2 by Materials Project

Na3Hg2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. there are three inequivalent Na sites. In the first Na site, Na is bonded in a 6-coordinate geometry to six equivalent Hg atoms. There are two shorter (3.16 Å) and four longer (3.30 Å) Na–Hg bond lengths. In the second Na site, Na is bonded in a distorted square co-planar geometry to four equivalent Hg atoms. All Na–Hg bond lengths are 3.40 Å. In the third Na site, Na is bonded in a 6-coordinate geometry to six equivalent Hg atoms. There are two shorter (3.19 Å) and four longer (3.34 Å) Na–Hg bond lengths. Hg is bonded in a 10-coordinate geometry to eight Na and two equivalent Hg atoms. Both Hg–Hg bond lengths are 3.07 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg6S4Br3Cl by Materials Project

Hg6S4Br3Cl crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are four inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to two S2-, two Br1-, and one Cl1- atom. Both Hg–S bond lengths are 2.46 Å. There are one shorter (3.14 Å) and one longer (3.54 Å) Hg–Br bond lengths. The Hg–Cl bond length is 2.84 Å. In the second Hg2+ site, Hg2+ is bonded to two equivalent S2- and three Br1- atoms to form distorted HgS2Br3 square pyramids that share corners with two equivalent HgS2Br4 octahedra, edges with two equivalent HgS2Br4 octahedra, and an edgeedge with one HgS2Br3 square pyramid. The corner-sharing octahedral tilt angles are 66°. Both Hg–S bond lengths are 2.46 Å. There are a spread of Hg–Br bond distances ranging from 2.97–3.29 Å. In the third Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to two equivalent S2-, two Br1-, and one Cl1- atom. Both Hg–S bond lengths are 2.45 Å. There are one shorter (3.34 Å) and one longer (3.39 Å) Hg–Br bond lengths. The Hg–Cl bond length is 2.83 Å. In the fourth Hg2+ site, Hg2+ is bonded to two S2- and four Br1- atoms to form distorted HgS2Br4 octahedra that share corners with four equivalent HgS2Br4 octahedra, a cornercorner with one HgS2Br3 square pyramid, edges with four equivalent HgS2Br4 octahedra, and an edgeedge with one HgS2Br3 square pyramid. The corner-sharing octahedra tilt angles range from 0–4°. Both Hg–S bond lengths are 2.44 Å. There are a spread of Hg–Br bond distances ranging from 3.20–3.48 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three Hg2+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three Hg2+ atoms. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 6-coordinate geometry to six Hg2+ atoms. In the second Br1- site, Br1- is bonded in a square co-planar geometry to four equivalent Hg2+ atoms. In the third Br1- site, Br1- is bonded in a 7-coordinate geometry to five Hg2+ atoms. In the fourth Br1- site, Br1- is bonded in a distorted body-centered cubic geometry to eight Hg2+ atoms. Cl1- is bonded in a distorted trigonal planar geometry to three Hg2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg2IO by Materials Project

Hg2OI crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of two Hg2OI sheets oriented in the (1, 0, 0) direction. there are two inequivalent Hg+1.50+ sites. In the first Hg+1.50+ site, Hg+1.50+ is bonded in a 6-coordinate geometry to three equivalent O2- and two equivalent I1- atoms. There are two shorter (2.20 Å) and one longer (2.62 Å) Hg–O bond lengths. There are one shorter (3.09 Å) and one longer (3.17 Å) Hg–I bond lengths. In the second Hg+1.50+ site, Hg+1.50+ is bonded in a single-bond geometry to one O2- atom. The Hg–O bond length is 2.17 Å. O2- is bonded to four Hg+1.50+ atoms to form a mixture of edge and corner-sharing OHg4 tetrahedra. I1- is bonded in a 2-coordinate geometry to two equivalent Hg+1.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg5(SbI3)2 by Materials Project

Hg5(SbI3)2 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are five inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a distorted rectangular see-saw-like geometry to one Sb2- and three I1- atoms. The Hg–Sb bond length is 2.75 Å. There are a spread of Hg–I bond distances ranging from 2.78–3.28 Å. In the second Hg2+ site, Hg2+ is bonded in a 1-coordinate geometry to one Sb2- and two I1- atoms. The Hg–Sb bond length is 2.73 Å. There are one shorter (2.73 Å) and one longer (3.41 Å) Hg–I bond lengths. In the third Hg2+ site, Hg2+ is bonded in a distorted rectangular see-saw-like geometry to one Sb2- and three I1- atoms. The Hg–Sb bond length is 2.74 Å. There are a spread of Hg–I bond distances ranging from 2.84–3.55 Å. In the fourth Hg2+ site, Hg2+ is bonded in a rectangular see-saw-like geometry to one Sb2- and three I1- atoms. The Hg–Sb bond length is 2.75 Å. There are a spread of Hg–I bond distances ranging from 2.98–3.14 Å. In the fifth Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to one Sb2- and four I1- atoms. The Hg–Sb bond length is 2.78 Å. There are a spread of Hg–I bond distances ranging from 2.83–3.87 Å. There are two inequivalent Sb2- sites. In the first Sb2- site, Sb2- is bonded in a 3-coordinate geometry to two Hg2+ and one Sb2- atom. The Sb–Sb bond length is 2.89 Å. In the second Sb2- site, Sb2- is bonded in a tetrahedral geometry to three Hg2+ and one Sb2- atom. There are six inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted L-shaped geometry to two Hg2+ atoms. In the second I1- site, I1- is bonded in a water-like geometry to two Hg2+ atoms. In the third I1- site, I1- is bonded in a distorted L-shaped geometry to two Hg2+ atoms. In the fourth I1- site, I1- is bonded in a distorted trigonal non-coplanar geometry to three Hg2+ atoms. In the fifth I1- site, I1- is bonded in a 2-coordinate geometry to three Hg2+ atoms. In the sixth I1- site, I1- is bonded in a 3-coordinate geometry to three Hg2+ atoms.

36 MATERIALS SCIENCE↗