Henry Kerfoot - Academia.edu (original) (raw)
Papers by Henry Kerfoot
Chemischer Informationsdienst, Jun 12, 1979
Waste Management, Jul 1, 2016
ABSTRACT This report describes a field evaluation of a passive-sampling technique for soil-gas su... more ABSTRACT This report describes a field evaluation of a passive-sampling technique for soil-gas surveying. The system uses a sampler, consisting of an industrial hygiene organic vapor monitor inside a metal-sampling manifold, buried at a depth of approximately 0.3 meters (1 foot). An absorbent sampler is buried at a shallow depth and allowed to collect VOCs from the soil atmosphere. After a set time (8 hours to several weeks), the sampler is retrieved, sealed immediately, and transported to a laboratory for analysis. Analysis results indicate the identity and concentration of VOCs collected by the sampler. The main advantage of passive sampling lies in the simplicity of field operations, that is, field support (supplies, personnel, and equipment) is much less costly than for grab sampling, and equipment problems are virtually non-existent. The disadvantages associated with passive sampling are that results are not available for days to weeks and that deep sampling is difficult without more elaborate equipment.
Water Resources and the Urban Environment, 1998
What causes wide-spread elevated temperatures in municipal solid waste (MSW) landfills? Why and h... more What causes wide-spread elevated temperatures in municipal solid waste (MSW) landfills? Why and how do some elevated temperature events expand to involve significant adjacent waste? These questions are inherently difficult to answer due to the infinite combinations and permutations of waste type, waste location, landfill geometry, cover conditions, gas management, leachate management, climate, moisture conditions, etc. at different MSW landfills and even different zones within a given landfill.
Environmental Science Technology, 1987
The Lockheed Gas Analysis System (LGAS) grab-sampling method and the PETREX Static Surface Trappi... more The Lockheed Gas Analysis System (LGAS) grab-sampling method and the PETREX Static Surface Trapping Pyrolysis/Mass Spectrometry (SST-Py/MS) passive sampling technique for soil-gas measurement have been field tested at the Pittman Lateral near Henderson, Nevada. This site has unconfined ground water at 5 to 14 feet (1.5 to 4.3m) below the surface in alluvial fan sediments. Distinct chloroform and benzene/chlorobenzene contaminant plumes cross the site and have been delineated by repeated analyses of ground water from a line of boreholes spaced 200 feet apart. The LGAS technique successfully measured a chloroform soil-gas plume above the chloroform ground-water plume. The chloroform concentrations in soil-gas samples correlate well with ground-water concentrations. Further research is needed to establish which factors limit the survey precision.
The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lanthanate(I... more The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lanthanate(III)) tetrahydrate, Na(La(H/sub 2/O)/sub 2/(C/sub 10/H/sub 8/O/sub 6/)/sub 2/) . 4H/sub 2/O are reported. Crystals obtained from aqueous solution are triclinic, space group P anti 1, with a = 12.350(4)A, b = 12.760(3)A, c = 8.783(3)A, ..cap alpha.. = 101.54(2)/sup 0/, ..beta.. = 95.28(2)/sup 0/, ..gamma.. = 75.98(2)/sup 0/, Z = 2, d/sub measd/ = 1.86(2) g cm/sup -3/, d/sub calcd/ = 1.81 g cm/sup -3/. Standard heavy-atom methods were employed in the structural solution. Full-matrix, least-squares refinement of the non-hydrogen atom parameters, based on 4337 counter-collected F/sub 0/'s, led to a final R value of 0.041 and a final weighted R value of 0.054. The lanthanum ion is decacoordinate, with a primary coordination sphere comprised of two tetradentate benzene-1,2-dioxydiacetate ligands and two water molecules. The coordination polyhedron about the lanthanum ion approximates a s-bicapped square antiprism, with typical La-O separations. Individual sodium ions are hexacoordinate and inversion-related sodium coordination polyhedra together form a distorted, edge-shared bioctahedron. The novel aspect of the structure is the multiple bridging between the lanthanum and sodium ion coordination spheres, primarily through the benzene-1,2-dioxydiacetate ligands. The molecular conformation of the lanthanum complex observed in this structure does not duplicatemore » that found in solution by NMR techniques. These conformational differences are attributable to interactions involving the coordinating sodium ion and other crystal packing forces not expected to be present in solution.« less
Journal of the Air & Waste Management Association, 1990
ABSTRACT A field evaluation of the performance of four portable gas chromatographs was conducted ... more ABSTRACT A field evaluation of the performance of four portable gas chromatographs was conducted at two field sites, one in the Pacific Northwest (chlorinated solvent contamination) and one in the Desert Southwest (primarily jet fuel contamination). The purpose of the study was to compare the performance of four portable GCs under the same conditions. The gas chromatographs had either electron-capture detectors or photoionization detectors. The study evaluated instrument linearity, instrument detection limits, retention time stabilities, response factor stability, and chromatographic performance. Standards and samples contained 1, 1, 2, 2-tetrachloroethane, trichloroethene, tetrachloroethane, 1, 1, 1-trichloroethane, benzene, toluene, and ethylbenzene. In order to ensure data comparability, the same model wide-bore column and computing integrator were used with each instrument, where possible. Significant differences in the performance of the four models were detected under the specific conditions used for this study. The results indicate the need to fully characterize the performance of portable instruments before field use so that appropriate quality control measures can be planned and implemented based on the performance of a specific analytical system.
Environmental science. Processes & impacts, 2013
At a municipal solid waste landfill in southern California (USA) overlying a natural gas reservoi... more At a municipal solid waste landfill in southern California (USA) overlying a natural gas reservoir, methane was detected at concentrations of up to 40% (by volume) in perimeter soil gas probes. Stable isotope and (14)C values of methane together with gas composition (major components and volatile organic compounds) data were evaluated to assess the relative contributions of landfill gas and natural gas to the measured methane concentrations. The data was further used to estimate the residence time of the landfill gas in the probes. Results showed that up to 37% of the measured methane was derived from landfill gas. In addition, the landfill gas in the probe samples has undergone extensive alteration due to dissolution of carbon dioxide in pore water. Data further indicates that the measured methane was released from the waste approximately 1.2 to 9.4 years ago, rather than representing evidence of an ongoing release.
Environmental Geosciences, 1998
ABSTRACT The properties of methyl tertiary-butyl ether (MTBE) that are pertinent to subsurface fa... more ABSTRACT The properties of methyl tertiary-butyl ether (MTBE) that are pertinent to subsurface fate and transport and their significance is discussed in the context of contaminant transport and remedial techniques. Due to its high water solubility relative to gasoline hydrocarbons, MTBE is more likely to be leached into groundwater or infiltration. Gasoline that is 11% MTBE (the nominal standard for air pollution uses) is determined to have the potential of creating groundwater concentrations of up to 3,990,000 μg/L and gas-phase concentrations of 85,000 mg/m3. Due to its high volatility when dissolved in gasoline, vapor extraction is an appropriate approach for remediation of vadose-zone MTBE contamination from gasoline releases. Comparison of vapor extraction remediation of vadose-zone MTBE contamination due to gasoline releases to remediation of benzene from gasoline releases or of neat PCE shows MTBE to be similar to those two contaminants for which the technique is often used. However, the high water solubility of MTBE makes stripping less effective as a remedial technique for dissolved concentrations. Statistics for Los Angeles and Ventura counties near Los Angeles, California, show that 82% of stations have concentrations above the California health advisory level of 35 μg/L in groundwater and that the thickness of the vadose zone has no effect on groundwater MTBE contamination. At one location in Southern California, MTBE was seen to represent the leading edge of the contaminant plume from a gasoline release, and MTBE effects on cross-gradient wells indicate that MTBE can migrate in the gas phase to affect groundwater that is not downgradient of the spill.
TrAC Trends in Analytical Chemistry, 1990
Abstract Sampling and analysis of subsurface pore gases is a technique that is finding increased ... more Abstract Sampling and analysis of subsurface pore gases is a technique that is finding increased application in preliminary evaluation of the extent and magnitude of subsurface contamination by volatile organic compounds. Relationships between pore-gas and subsurface contaminant concentrations can be affected by contaminant transport or transformation and caution must be used in interpretation of results.
The Resource Conservation and Recovery Act (RCRA) requires landfill operators to monitor groundwa... more The Resource Conservation and Recovery Act (RCRA) requires landfill operators to monitor groundwater at their facilities. This regulatory requirement is designed to prevent contamination that can result as rainfall drains through refuse, causing pollutants to leach into the groundwater. Several parameters commonly associated with leachate are monitored under RCRA as indicator parameters, or parameters that represent readily detected indicators of contamination. These parameters include volatile organic compounds (VOCs) and alkalinity. Because of its potentially high concentration of VOCs and non-volatile contaminants, landfill leachate represents the greatest threat to groundwater from solid waste facilities. However, other sources can elevate indicator parameters as well. Increasingly lower detection limits can be achieved for VOCs in groundwater, enabling detection of VOCs and carbon dioxide (COâ) from landfill gas. In addition, COâ from landfill gas can increase groundwater alkal...
Journal of Environmental Monitoring, 2003
An evaluation of the source of volatile organic compounds in groundwater samples was performed at... more An evaluation of the source of volatile organic compounds in groundwater samples was performed at a landfill in southern California. The 3H (tritium) content of the water in leachate and water from the gas-collection system (condensed water and entrained water droplets) and the delta 13C and 14C content of the inorganic carbon in landfill gas CO2, leachate, and gas-collection system water were used to characterize the dissolved inorganic carbon (DIC) inside the landfill, while the same parameters were monitored in groundwater samples from affected monitoring wells and an unaffected well. Tritium levels from leachate and gas-collection system condensate ranged from approximately 2000 TU to over 4000 TU, orders of magnitude higher than unaffected groundwater. The average 14C content of DIC in the landfill pore-water samples was 121 pMC and the 14C content of unaffected groundwater DIC was 93 pMC, while the 14C content of the dissolved inorganic carbon in groundwater with VOC detections ranged from 105 to 119 pMC. The delta 13C of DIC in pore water was consistently above 0 per thousand and the delta 13C of unaffected groundwater DIC was -20.3 per thousand, while the delta 13C of DIC in affected groundwater samples was increased from -17.3 to -13.2 per thousand. The increases in both delta 13C and 14C in landfill gas-impacted groundwater DIC generally correlated with the number of volatile organic compounds detected and their concentrations. Based on the tritium and DIC 14C levels in leachate and water from the gas-collection system compared to those of unaffected water, significant increases in the tritium content of the water would be expected to accompany VOC detections and increases in delta 13C and 14C caused by landfill water. The results rule out landfill water as the VOC source, leaving landfill gas as the source. The identities and concentrations of the specific VOCs in affected groundwater samples varied among wells as well as between two leachate samples, ruling out the use of a VOC "fingerprint" for leachate or landfill gas to be compared to groundwater VOC concentrations.
![Research paper thumbnail of Crystal data for the tetraphenylarsonium salt of the monoanion of theophylline, [(C6H5)4As] [C7N4O2H7].5H2O](https://attachments.academia-assets.com/119582681/thumbnails/1.jpg)
](Journal of Applied Crystallography, 1975
Journal of Applied Crystallography, 1976
International Journal of Environmental Analytical Chemistry, 1987
... meters (20 feet) down wind. Water samples were taken in 45-mL septum-capped vials (Pierce Che... more ... meters (20 feet) down wind. Water samples were taken in 45-mL septum-capped vials (Pierce Chemical Company) and were analyzed by US. Environmental Protection Agency procedures using a Finnegan GC/MS6 Procedure ...
Inorganic Chemistry, 1979
ABSTRACT The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lan... more ABSTRACT The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lanthanate(III)) tetrahydrate, Na(La(HâO)â(CââHâOâ)â) . 4HâO are reported. Crystals obtained from aqueous solution are triclinic, space group P anti 1, with a = 12.350(4)A, b = 12.760(3)A, c = 8.783(3)A, ..cap alpha.. = 101.54(2)°, ..beta.. = 95.28(2)°, ..gamma.. = 75.98(2)°, Z = 2, d/sub measd/ = 1.86(2) g cmâ»Â³, d/sub calcd/ = 1.81 g cmâ»Â³. Standard heavy-atom methods were employed in the structural solution. Full-matrix, least-squares refinement of the non-hydrogen atom parameters, based on 4337 counter-collected Fâ's, led to a final R value of 0.041 and a final weighted R value of 0.054. The lanthanum ion is decacoordinate, with a primary coordination sphere comprised of two tetradentate benzene-1,2-dioxydiacetate ligands and two water molecules. The coordination polyhedron about the lanthanum ion approximates a s-bicapped square antiprism, with typical La-O separations. Individual sodium ions are hexacoordinate and inversion-related sodium coordination polyhedra together form a distorted, edge-shared bioctahedron. The novel aspect of the structure is the multiple bridging between the lanthanum and sodium ion coordination spheres, primarily through the benzene-1,2-dioxydiacetate ligands. The molecular conformation of the lanthanum complex observed in this structure does not duplicate that found in solution by NMR techniques. These conformational differences are attributable to interactions involving the coordinating sodium ion and other crystal packing forces not expected to be present in solution.
Ground Water Monitoring & Remediation, 1988
Chemischer Informationsdienst, Jun 12, 1979
Waste Management, Jul 1, 2016
ABSTRACT This report describes a field evaluation of a passive-sampling technique for soil-gas su... more ABSTRACT This report describes a field evaluation of a passive-sampling technique for soil-gas surveying. The system uses a sampler, consisting of an industrial hygiene organic vapor monitor inside a metal-sampling manifold, buried at a depth of approximately 0.3 meters (1 foot). An absorbent sampler is buried at a shallow depth and allowed to collect VOCs from the soil atmosphere. After a set time (8 hours to several weeks), the sampler is retrieved, sealed immediately, and transported to a laboratory for analysis. Analysis results indicate the identity and concentration of VOCs collected by the sampler. The main advantage of passive sampling lies in the simplicity of field operations, that is, field support (supplies, personnel, and equipment) is much less costly than for grab sampling, and equipment problems are virtually non-existent. The disadvantages associated with passive sampling are that results are not available for days to weeks and that deep sampling is difficult without more elaborate equipment.
Water Resources and the Urban Environment, 1998
What causes wide-spread elevated temperatures in municipal solid waste (MSW) landfills? Why and h... more What causes wide-spread elevated temperatures in municipal solid waste (MSW) landfills? Why and how do some elevated temperature events expand to involve significant adjacent waste? These questions are inherently difficult to answer due to the infinite combinations and permutations of waste type, waste location, landfill geometry, cover conditions, gas management, leachate management, climate, moisture conditions, etc. at different MSW landfills and even different zones within a given landfill.
Environmental Science Technology, 1987
The Lockheed Gas Analysis System (LGAS) grab-sampling method and the PETREX Static Surface Trappi... more The Lockheed Gas Analysis System (LGAS) grab-sampling method and the PETREX Static Surface Trapping Pyrolysis/Mass Spectrometry (SST-Py/MS) passive sampling technique for soil-gas measurement have been field tested at the Pittman Lateral near Henderson, Nevada. This site has unconfined ground water at 5 to 14 feet (1.5 to 4.3m) below the surface in alluvial fan sediments. Distinct chloroform and benzene/chlorobenzene contaminant plumes cross the site and have been delineated by repeated analyses of ground water from a line of boreholes spaced 200 feet apart. The LGAS technique successfully measured a chloroform soil-gas plume above the chloroform ground-water plume. The chloroform concentrations in soil-gas samples correlate well with ground-water concentrations. Further research is needed to establish which factors limit the survey precision.
The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lanthanate(I... more The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lanthanate(III)) tetrahydrate, Na(La(H/sub 2/O)/sub 2/(C/sub 10/H/sub 8/O/sub 6/)/sub 2/) . 4H/sub 2/O are reported. Crystals obtained from aqueous solution are triclinic, space group P anti 1, with a = 12.350(4)A, b = 12.760(3)A, c = 8.783(3)A, ..cap alpha.. = 101.54(2)/sup 0/, ..beta.. = 95.28(2)/sup 0/, ..gamma.. = 75.98(2)/sup 0/, Z = 2, d/sub measd/ = 1.86(2) g cm/sup -3/, d/sub calcd/ = 1.81 g cm/sup -3/. Standard heavy-atom methods were employed in the structural solution. Full-matrix, least-squares refinement of the non-hydrogen atom parameters, based on 4337 counter-collected F/sub 0/'s, led to a final R value of 0.041 and a final weighted R value of 0.054. The lanthanum ion is decacoordinate, with a primary coordination sphere comprised of two tetradentate benzene-1,2-dioxydiacetate ligands and two water molecules. The coordination polyhedron about the lanthanum ion approximates a s-bicapped square antiprism, with typical La-O separations. Individual sodium ions are hexacoordinate and inversion-related sodium coordination polyhedra together form a distorted, edge-shared bioctahedron. The novel aspect of the structure is the multiple bridging between the lanthanum and sodium ion coordination spheres, primarily through the benzene-1,2-dioxydiacetate ligands. The molecular conformation of the lanthanum complex observed in this structure does not duplicatemore » that found in solution by NMR techniques. These conformational differences are attributable to interactions involving the coordinating sodium ion and other crystal packing forces not expected to be present in solution.« less
Journal of the Air & Waste Management Association, 1990
ABSTRACT A field evaluation of the performance of four portable gas chromatographs was conducted ... more ABSTRACT A field evaluation of the performance of four portable gas chromatographs was conducted at two field sites, one in the Pacific Northwest (chlorinated solvent contamination) and one in the Desert Southwest (primarily jet fuel contamination). The purpose of the study was to compare the performance of four portable GCs under the same conditions. The gas chromatographs had either electron-capture detectors or photoionization detectors. The study evaluated instrument linearity, instrument detection limits, retention time stabilities, response factor stability, and chromatographic performance. Standards and samples contained 1, 1, 2, 2-tetrachloroethane, trichloroethene, tetrachloroethane, 1, 1, 1-trichloroethane, benzene, toluene, and ethylbenzene. In order to ensure data comparability, the same model wide-bore column and computing integrator were used with each instrument, where possible. Significant differences in the performance of the four models were detected under the specific conditions used for this study. The results indicate the need to fully characterize the performance of portable instruments before field use so that appropriate quality control measures can be planned and implemented based on the performance of a specific analytical system.
Environmental science. Processes & impacts, 2013
At a municipal solid waste landfill in southern California (USA) overlying a natural gas reservoi... more At a municipal solid waste landfill in southern California (USA) overlying a natural gas reservoir, methane was detected at concentrations of up to 40% (by volume) in perimeter soil gas probes. Stable isotope and (14)C values of methane together with gas composition (major components and volatile organic compounds) data were evaluated to assess the relative contributions of landfill gas and natural gas to the measured methane concentrations. The data was further used to estimate the residence time of the landfill gas in the probes. Results showed that up to 37% of the measured methane was derived from landfill gas. In addition, the landfill gas in the probe samples has undergone extensive alteration due to dissolution of carbon dioxide in pore water. Data further indicates that the measured methane was released from the waste approximately 1.2 to 9.4 years ago, rather than representing evidence of an ongoing release.
Environmental Geosciences, 1998
ABSTRACT The properties of methyl tertiary-butyl ether (MTBE) that are pertinent to subsurface fa... more ABSTRACT The properties of methyl tertiary-butyl ether (MTBE) that are pertinent to subsurface fate and transport and their significance is discussed in the context of contaminant transport and remedial techniques. Due to its high water solubility relative to gasoline hydrocarbons, MTBE is more likely to be leached into groundwater or infiltration. Gasoline that is 11% MTBE (the nominal standard for air pollution uses) is determined to have the potential of creating groundwater concentrations of up to 3,990,000 μg/L and gas-phase concentrations of 85,000 mg/m3. Due to its high volatility when dissolved in gasoline, vapor extraction is an appropriate approach for remediation of vadose-zone MTBE contamination from gasoline releases. Comparison of vapor extraction remediation of vadose-zone MTBE contamination due to gasoline releases to remediation of benzene from gasoline releases or of neat PCE shows MTBE to be similar to those two contaminants for which the technique is often used. However, the high water solubility of MTBE makes stripping less effective as a remedial technique for dissolved concentrations. Statistics for Los Angeles and Ventura counties near Los Angeles, California, show that 82% of stations have concentrations above the California health advisory level of 35 μg/L in groundwater and that the thickness of the vadose zone has no effect on groundwater MTBE contamination. At one location in Southern California, MTBE was seen to represent the leading edge of the contaminant plume from a gasoline release, and MTBE effects on cross-gradient wells indicate that MTBE can migrate in the gas phase to affect groundwater that is not downgradient of the spill.
TrAC Trends in Analytical Chemistry, 1990
Abstract Sampling and analysis of subsurface pore gases is a technique that is finding increased ... more Abstract Sampling and analysis of subsurface pore gases is a technique that is finding increased application in preliminary evaluation of the extent and magnitude of subsurface contamination by volatile organic compounds. Relationships between pore-gas and subsurface contaminant concentrations can be affected by contaminant transport or transformation and caution must be used in interpretation of results.
The Resource Conservation and Recovery Act (RCRA) requires landfill operators to monitor groundwa... more The Resource Conservation and Recovery Act (RCRA) requires landfill operators to monitor groundwater at their facilities. This regulatory requirement is designed to prevent contamination that can result as rainfall drains through refuse, causing pollutants to leach into the groundwater. Several parameters commonly associated with leachate are monitored under RCRA as indicator parameters, or parameters that represent readily detected indicators of contamination. These parameters include volatile organic compounds (VOCs) and alkalinity. Because of its potentially high concentration of VOCs and non-volatile contaminants, landfill leachate represents the greatest threat to groundwater from solid waste facilities. However, other sources can elevate indicator parameters as well. Increasingly lower detection limits can be achieved for VOCs in groundwater, enabling detection of VOCs and carbon dioxide (COâ) from landfill gas. In addition, COâ from landfill gas can increase groundwater alkal...
Journal of Environmental Monitoring, 2003
An evaluation of the source of volatile organic compounds in groundwater samples was performed at... more An evaluation of the source of volatile organic compounds in groundwater samples was performed at a landfill in southern California. The 3H (tritium) content of the water in leachate and water from the gas-collection system (condensed water and entrained water droplets) and the delta 13C and 14C content of the inorganic carbon in landfill gas CO2, leachate, and gas-collection system water were used to characterize the dissolved inorganic carbon (DIC) inside the landfill, while the same parameters were monitored in groundwater samples from affected monitoring wells and an unaffected well. Tritium levels from leachate and gas-collection system condensate ranged from approximately 2000 TU to over 4000 TU, orders of magnitude higher than unaffected groundwater. The average 14C content of DIC in the landfill pore-water samples was 121 pMC and the 14C content of unaffected groundwater DIC was 93 pMC, while the 14C content of the dissolved inorganic carbon in groundwater with VOC detections ranged from 105 to 119 pMC. The delta 13C of DIC in pore water was consistently above 0 per thousand and the delta 13C of unaffected groundwater DIC was -20.3 per thousand, while the delta 13C of DIC in affected groundwater samples was increased from -17.3 to -13.2 per thousand. The increases in both delta 13C and 14C in landfill gas-impacted groundwater DIC generally correlated with the number of volatile organic compounds detected and their concentrations. Based on the tritium and DIC 14C levels in leachate and water from the gas-collection system compared to those of unaffected water, significant increases in the tritium content of the water would be expected to accompany VOC detections and increases in delta 13C and 14C caused by landfill water. The results rule out landfill water as the VOC source, leaving landfill gas as the source. The identities and concentrations of the specific VOCs in affected groundwater samples varied among wells as well as between two leachate samples, ruling out the use of a VOC "fingerprint" for leachate or landfill gas to be compared to groundwater VOC concentrations.
Journal of Applied Crystallography, 1975
Journal of Applied Crystallography, 1976
International Journal of Environmental Analytical Chemistry, 1987
... meters (20 feet) down wind. Water samples were taken in 45-mL septum-capped vials (Pierce Che... more ... meters (20 feet) down wind. Water samples were taken in 45-mL septum-capped vials (Pierce Chemical Company) and were analyzed by US. Environmental Protection Agency procedures using a Finnegan GC/MS6 Procedure ...
Inorganic Chemistry, 1979
ABSTRACT The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lan... more ABSTRACT The preparation and crystal structure of sodium(diaquobis(benzene-1,2-dioxydiacetato)lanthanate(III)) tetrahydrate, Na(La(HâO)â(CââHâOâ)â) . 4HâO are reported. Crystals obtained from aqueous solution are triclinic, space group P anti 1, with a = 12.350(4)A, b = 12.760(3)A, c = 8.783(3)A, ..cap alpha.. = 101.54(2)°, ..beta.. = 95.28(2)°, ..gamma.. = 75.98(2)°, Z = 2, d/sub measd/ = 1.86(2) g cmâ»Â³, d/sub calcd/ = 1.81 g cmâ»Â³. Standard heavy-atom methods were employed in the structural solution. Full-matrix, least-squares refinement of the non-hydrogen atom parameters, based on 4337 counter-collected Fâ's, led to a final R value of 0.041 and a final weighted R value of 0.054. The lanthanum ion is decacoordinate, with a primary coordination sphere comprised of two tetradentate benzene-1,2-dioxydiacetate ligands and two water molecules. The coordination polyhedron about the lanthanum ion approximates a s-bicapped square antiprism, with typical La-O separations. Individual sodium ions are hexacoordinate and inversion-related sodium coordination polyhedra together form a distorted, edge-shared bioctahedron. The novel aspect of the structure is the multiple bridging between the lanthanum and sodium ion coordination spheres, primarily through the benzene-1,2-dioxydiacetate ligands. The molecular conformation of the lanthanum complex observed in this structure does not duplicate that found in solution by NMR techniques. These conformational differences are attributable to interactions involving the coordinating sodium ion and other crystal packing forces not expected to be present in solution.
Ground Water Monitoring & Remediation, 1988