Vacuum Dehydration Research Articles

Kinetic Isotope Effects in Oxygen in the Laboratory Dehydration of Magnesian Minerals

Laboratory studies of vacuum dehydration of Mg-O-H units in minerals and rocks reveal large kinetic isotope effects in oxygen, with light-isotope enrichment in the liberated water, and concomitant heavy-isotope enrichment in the residual solids. Application of the same techniques to a meteorite assemblage including hydrous magnesium silicates shows a much more complex behavior, probably due to isotopic heterogeneity inherited from processes on the meteorite parent body. Measurements of both the (17)O/(16)O variations and the (18)O/(16)O variations confirm theoretical predictions that slopes of three-isotope correlation lines are systematically larger for equilibrium isotope effects than for kinetic isotope effects.

Solid-Polymer-Electrolyte Tritiated Water Electrolyzer for Water Detritiation System

A solid-polymer-electrolyte (SPE) water electrolyzer for high-level tritiated water was designed for the Water Detritiation System (WDS). Polymeric materials were selected from a main viewpoint of radiation durability to keep their functions beyond ITER-WDS requirement (530kGy). Our selection was Pt + Ir applied Nafion® N117 ion exchange membrane, VITON® O-ring seal and polyimide insulator. A γ-ray irradiation test of the SPE cell demonstrated the durability of the cell against 530kGy. The electrolyzer is designed to handle around 9TBq/kg of high-level tritiated water. The detritiation of the polymeric materials is thus a critical problem for the maintenance or for the disposal of the electrolyzer. As for the Nafion membrane, most of tritiated water in the membrane was rapidly removed by such as vacuum dehydration. It was difficult, by contrast, to remove bound tritiated water in the membrane. An effective method to remove tritiated water in the bound water is to promote an isotope exchange.

Combined oxygen and silicon isotope analysis of biogenic silica

AbstractThere is increasing interest in the use of biogenic silica O and Si isotope ratios to understand climate and environmental processes. Virtually all of the fairly substantial body of literature deals with either oxygen or silicon. This is partly because measurement of oxygen isotope composition is done using either vacuum dehydration, isotope exchange or stepped fluorination techniques, while increasingly researchers are turning to multicollector inductively coupled plasma mass spectrometry (MC‐ICP‐MS) for Si isotope analysis, even though Si isotope analysis can be done using fluorination methods used for the oxygen isotope measurements. Here we describe a procedure for simultaneous determination of isotopic abundances of oxygen and silicon from the same aliquot of biogenic silica. Pure silica is dissociated into O and Si compounds using a fluorination technique, in which reaction with bromine pentafluoride (BrF5) produces oxygen (O2, subsequently converted to CO2), silicon tetrafluoride (SiF4) and other fluorine by‐products (e.g. BrF3). These compounds are cryogenically separated using cold traps. Yields for oxygen and silicon recovery are 70–80% for biogenic silica depending on the nature of the hydrous layer and 97–99% for pure quartz. Reproducibility of the oxygen isotopic composition is ca. 0.3‰ and silicon between 0.06–0.12‰. © Natural Environment Research Council (NERC) copyright 2008. Reproduced with the permission of NERC. Published by John Wiley & Sons, Ltd.

High Processing Tolerances of Immunomodulatory Proteins in Enoki and Reishi Mushrooms

This study investigated the processing tolerances of two mushroom proteins with immunomodulatory activities, including FVE from Enoki ( Flammulia velutipes ) and LZ8 from Reishi ( Ganoderma lucidum ) mushrooms, under food processing treatments such as heating, sterilization, frozen storage, extraction in acid/alkaline conditions, and dehydration. Results showed that the capability of these two proteins to induce IFN-gamma secretion by murine splenocytes remained after 100 degrees C heating for 30 min, 121 degrees C autoclaving for 15 min, and -80 degrees C freezing. The retained activities of both proteins on cell proliferation and IFN-gamma production did not decrease at 0.6 M hydrochloric acid (at pH 2) but strikingly dropped at 5 M sodium hydrate (at pH 13). After vacuum dehydration, FVE and LZ8 retained most of their activities on cell proliferation; nevertheless, the IFN-gamma secretion decreased to about half of the initial values. These findings suggest that these two mushroom proteins have a good thermal/freezing resistance, acid tolerance, and dehydration stability and are candidates for processing in food and nutraceutical utilization.

Effect of Etching Time on Porous Silicon Formation

The electrochemical responses, microstructures and surface species of porous silicon (PS) formed on n (111) silicon at different etching time were investigated by electrochemical polarization, SEM, Raman and FTIR techniques. The kinetic parameters of electrochemical reactions were calculated from the Tafel slopes. The chemical stability was characterized by aging the fresh PS samples stored in the vacuum desiccator. The PS structure of larger pores (∼20 nm) was formed within 1 min, however, the pore sizes decreased with the increase of etching time and became relatively stable up to 10 min. The larger pores were observed afterwards due to the mergence of the small pores. The growth rate of PS was proportional to the etching time. The FTIR spectra revealed that the surface species were mainly identified as SiH and SiH2, and the PS microstructures could be chemically stable for 4 days in the vacuum desiccator.

Adsorption of hydrogen in nickel and rhodium exchanged zeolite X

Adsorption of hydrogen in zeolite NaX and its nickel and rhodium exchanged forms were investigated at 77.4 K using a static volumetric adsorption system up to 1 bar, and at 303 and 333 K in a gravimetric adsorption system up to 5 bar. Hydrogen adsorption at 77.4 K for NaX and the nickel and rhodium exchanged zeolite X was found to be reversible with pressure. However, chemisorption of hydrogen was observed at 303 and 333 K. The highest adsorption capacities for hydrogen in NaX, NiNaX and RhNaX were observed to be 24.28, 34.51 and 51.85 molecule/u.c at 333 K and 5 bar. Hydrogen uptake capacities of the nickel and rhodium exchanged zeolite X at 303 and 333 K were found increasing initially up to 70% of nickel and 55% of rhodium exchange, beyond which it showed a decreasing trend. The observed decrease in adsorption capacity at higher Ni and Rh cation exchange is explained in terms of partial degradation of the zeolite structure during cation exchange and the high temperature vacuum dehydration process. Grand Canonical Monte Carlo simulations were also performed to study the adsorption of hydrogen in NaX as well as nickel and rhodium exchanged zeolites X at 77.4, 303 and 333 K and the simulated data were compared with experimentally measured values.

Compressive characteristics of cellular solids produced using vacuum-microwave, freeze, vacuum and hot air dehydration methods

Dried cellular solids were produced using different hydrocolloids such as locust bean gum, low methoxy pectin, methyl cellulose and tapioca starch. They were dried to less than 5% (w.b) moisture content using freeze-drying, vacuum drying, vacuum microwave drying or air-drying methods. The dry cellular solids were subjected to uniaxial compression using a Texture analyzer to study the compressive characteristics. True stress–strain relationship curves were developed for the dry cellular solids produced by different drying methods. Hencky’s strain was calculated for true strain. Comparisons of samples dried by different drying methods were done in terms of their compressive characteristics at various water activities. No matter the type of drying, the dried materials were brittle at low water activity, plastic at medium water activity and elastomeric at higher water activity levels. Due to non-uniformity in air-dried samples and more closed pores in vacuum dried samples as well as less mechanical strength, these two were considered inferior for production of strong elastomeric foams. Microwave vacuum dried foams were mechanically the strongest. All the microwave vacuum dried samples were close in their Young’s modulus. Increases in microwave power did not make any appreciable changes in pore structures although higher microwave power levels resulted in faster drying.

Quality and Physiochemical Properties of Banana Paste under Vacuum Dehydration

This research aimed to develop a prototype of an evaporative dehydrator and demonstrate the effect of quick evaporative dehydration on the physiochemical properties of banana paste. The study was divided into 2 parts. The first part was focused on the development of the evaporative dehydrator prototype. After several modifications, the prototype of an evaporative dehydrator was successfully constructed to enable the variation of banana paste sample prior to evaporation using two types of evaporative stresses (i.e., atmospheric and vacuum conditions). The second part was to study the effect of evaporative dehydration on the physiochemical properties of banana paste comparing vacuum and atmospheric conditions. The temperature setting for the heating section was varied at 30, 40, 60, 80, 100 and 120 degree Celsius and the physiochemical alteration of the banana paste sample was monitored. The peroxidase enzyme was found to be active in all treatments. The evaporative cooling in the vacuum treatment caused the temperature of the final product to be lower than that of the atmospheric treatment. The moisture content also seemed to be lower and the water activity was less. Although the acidity remained stable and was not differentiable between the two treatments; the different evaporative conditions had a profound effect on other physiochemical properties, especially the external appearance of the final product. The visual appearance was determined by the Hunter indices (L, a, and b) and delta E (overall color change). As the operating temperature increased, the delta E in both treatments increased. The sample in the vacuum treatment became darker (lower L-value) and more intense in yellow color (higher b-value). This was hypothesized to be the result of product condensation due to moisture loss. The a-value decreased as the operating temperature increased and there was no significant difference between the two treatments. The viscosity of the final product had a unique profile regarding the operating temperature variation. It appeared to be more viscous than the fresh sample at low temperature. For the higher temperature setting, the viscosity decreased as the temperature increased. Enzymatic and non-enzymatic chemical reactions might be responsible for the alteration of the flow characteristics of dehydrated sample rather than the sole effect of moisture reduction.

Improving Grape Quality Using Microwave Vacuum Drying Associated with Temperature Control

Microwave (MW) vacuum dehydration using temperature to control the level of MW power demonstrated potential in improving the performance of the process. Product surface temperature measured by an infrared temperature sensor was used to control MW power at any level between 0 and 3 kW. Multiple linear regression analysis indicated an r2 = 0.942 for prediction of final moisture content and r2 = 0.985 for prediction of puffed character of grapes based on product temperature, time, specific energy, fresh fruit sugar, and fresh fruit moisture content. Temperature was found to be the most significant predictor. The elemental and compound contents of grapes dried using MW vacuum was compared to sun-dried raisins. The grapes dried using MW vacuum exhibited better preservation. Vitamin A was found in the MW-vacuum-dried grapes but none was detected in the raisins, and Vitamin C, thiamine, and riboflavin were also higher in the MW-vacuum-dried grapes than in the raisins.

Mushroom immunomodulatory proteins possess potential thermal/freezing resistance, acid/alkali tolerance and dehydration stability

Mushroom lectins have been reported as immunomodulatory proteins. To evaluate their functionalities, as affected by various industrial procedures, two mushroom proteins, including Agaricus bisporus lectin (ABL) and the immunomodulatory protein of Auricularia polytricha (APP), were treated by various methods, mimicking food processing procedures, in prior-to-cell experiments, and their macrophage-activating functionalities were determined in the induction of tumor necrosis factor-alpha (TNF-α) and nitric oxide (NO) productions by RAW264.7 cells in vitro. The remaining activities of ABL and APP, after autoclave treatment (121 °C, 15 min), were observed to be 77.4% and 80.7%, respectively, in their stimulations of TNF-α production by cells. Boiling (100 °C, 30 min) and freezing (−80 °C, 24 h) treatments did not reduce their effects on TNF-α and NO secretions, while treating with pH 2 and pH 13 buffers only resulted in insignificant decrease of the ABL- and APP-induced TNF-α and NO production. Moreover, ABL and APP also withstood vacuum dehydration with 96.5% and 84.6% of activities being retained, respectively, in their stimulations of TNF-α production. These findings revealed that ABL and APP had thermal/freezing-resistant, acid/alkali tolerance and dehydration stable properties, and that they were potential candidates, as stable immune stimulants, for health food and pharmaceutical utilization.

Preparation, Crystal Structure, and Thermal Stability of the Cadmium Sulfide Nanoclusters Cd6S44+ and Cd2Na2S4+ in the Sodalite Cavities of Zeolite A (LTA)

The crystal structure and thermal stability of two cadmium sulfide nanoclusters prepared in zeolite A (LTA) have been studied by XPS, TGA, and single-crystal and powder XRD. The crystal structures of Cd2.4Na3.2(Cd6S4)0.4(Cd2Na2S)0.6(H2O)> or =5.8[Si12Al12O48]-LTA (a = 12.2919(7) A, crystal 1 (hydrated)) and /Cd4Na2(Cd2O)(Na2O)/[Si12Al12O48]-LTA (a = 12.2617(4) A, crystal 2 (dehydrated)) were determined by single-crystal methods in the cubic space group Pm3m at 294(1) K. Crystal 1 was prepared by ion exchange of Na12-LTA in an aqueous stream 0.05 M in Cd2+, followed by washing in a stream of water, followed by reaction in an aqueous stream 0.05 M in Na2S. Crystal 2 was made by dehydrating crystal 1 at 623 K and 1 x 10(-6) Torr for 3 days. In crystal 1, Cd6S4(4+) nanoclusters were found in and extending out of about 40% of the sodalite cavities. Central to each Cd6S4(4+) cluster is a Cd4S4 unit (interpenetrating Cd2+ and S2- tetrahedra with near Td symmetry, Cd-S = 2.997(24) A, Cd-S-Cd = 113.8(12) degrees, and S-Cd-S = 58.1(24) degrees). Each of the two remaining Cd2+ ions bonds radially through a 6-ring of the zeolite framework to a sulfide ion of this Cd4S4 unit (Cd-S = 2.90(8) A). In each of the remaining 60% of the sodalite cavities of crystal 1, a planar Cd2Na2S4+ cluster was found (Cd-S/Na-S = 2.35(5)/2.56(14) A and Cd-S-Cd/Na-S-Na = 122(5)/92(7) degrees). Cd6S4(4+) and Cd2Na2S4+ are stable within the zeolite up to about 700 K in air. Upon vacuum dehydration at 623 K, all sulfur was lost (crystal 2). Instead as anions, only two oxide ions remain per sodalite unit. One bridges between two Cd2+ ions (Cd2O2+, Cd-O = 2.28(3) A) and the other between two Na+ ions (Na2O, Na-O = 2.21(10) A).

FLAVOR AND AROMA ATTRIBUTES OF RIESLING WINES PRODUCED BY FREEZE CONCENTRATION AND MICROWAVE VACUUM DEHYDRATION

This article describes the production of sweet dessert wines produced using late-harvest freeze concentration, wine produced from fresh grapes frozen using refrigeration and wine produced from grapes partially dried using microwave vacuum dehydration. The objective was to compare the aroma and flavor attributes of the wines to determine the effect of each method of juice concentration. The replicated wine samples were evaluated by 12 experienced judges, and the wines were analyzed using solid-phase microextraction. The microextraction detected 28 compounds; however, levels of concentration of these compounds were below published aroma thresholds. Although all the wines were judged as acceptable sweet dessert wines, the judges detected significant differences. The wine made from the dehydrated grapes exhibited lower fresh fruit aroma, higher fusel oils and oxidation, and flavor notes including citrus/grapefruit and acidity were lower.

Single crystal structure of fully dehydrated fully Tl +-exchanged zeolite Y, ∣Tl 71∣[Si 121Al 71O 384]- FAU

The structure of fully dehydrated, fully Tl +-exchanged zeolite Y, ∣Tl 71∣[Si 121Al 71O 384]- FAU ( a = 24.948(2) Å), has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd 3 ¯ m at 21(1) °C. An aqueous exchange solution 0.05 M in Tl + with pH = 7.2 was allowed to flow past the crystal for 7 days. The resulting colorless crystal became black after being dehydrated at 400 °C and 2 × 10 −6 Torr for 2 days. Diffraction data were then gathered and were refined using all 702 unique reflections to the final error indices (based upon the 365 reflections for which F o > 4 σ( F o)) R 1 = 0.058 and wR 2 = 0.130. In this structure, Tl + ions occupy four crystallographic sites. About 30.4(6) Tl + ions fill or nearly fill site I′ in the sodalite cavities on 3-fold axes opposite double 6-rings; each is 1.37 Å from the plane of three oxygens (Tl–O = 2.568(17) Å, O–Tl–O = 93.9(5)°). Each is also 3.673(4) Å from three (perhaps sometimes only two) equivalent site-I′ Tl + ions. Thirty-two Tl + ions fill site II opposite single 6-rings in the supercage; each is 1.63 Å from the plane of three oxygens (Tl–O = 2.724(15) Å, O–Tl–O = 87.9(6)°). The remaining Tl + ions are located at two nonequivalent sites III′ with occupancies of 5.7(8) and 3.0(4) per unit cell; each coordinates to three framework oxygens. It appears that TlOH was imbibed during aqueous ion exchange at pH = 7.2, and that it decomposed upon vacuum dehydration at 400 °C to deposit as Tl 2O (black) on the surface of the zeolite crystal.

Saposin B binds and transfers phospholipids

Saposin B (Sap B) is a member of a family of four small glycoproteins, Sap A, B, C, and D. Like the other three saposins, Sap B plays a physiological role in the lysosomal degradation of sphingolipids (SLs). Although the interaction of Sap B with SLs has been investigated extensively, that with the main membrane lipid components, namely phospholipids and cholesterol (Chol), is scarcely known. Using large unilamellar vesicles (LUVs) as membrane models, we have now found that Sap B simultaneously extracts from the lipid surface neutral [phosphatidylcholine (PC)] and anionic [phosphatidylinositol (PI)] phospholipids, fewer SLs [ganglioside GM1 (GM1) or cerebroside sulfate (CS)], and no Chol. More PI than SL (GM1 or CS) was solubilized from LUVs containing equal amounts of PI and SLs. An increase in PI level had a poor effect on the Sap B-induced solubilization of GM1 or CS but strongly inhibited that of PC. Sap B was able not only to bind, but also to transfer phospholipids between lipid surfaces. Both the phospholipid binding and transfer activities were optimal at low pH values. These results represent the first biochemical analysis of the Sap B interaction with phospholipids. The capacity of Sap B to bind and transfer phospholipids occurs under conditions mimicking the interior of the late endosomal/lysosomal compartment and thus might have physiological relevance.

Lipids isolated from bone induce the migration of human breast cancer cells

Bone is the most common site to which breast cancer cells metastasize. We found that osteoblast-like MG63 cells and human bone tissue contain the bile acid salt sodium deoxycholate (DC). MG63 cells take up and accumulate DC from the medium, suggesting that the bone-derived DC originates from serum. DC released from MG63 cells or bone tissue promotes cell survival and induces the migration of metastatic human breast cancer MDA-MB-231 cells. The bile acid receptor farnesoid X receptor (FXR) antagonist Z-guggulsterone prevents the migration of these cells and induces apoptosis. DC increases the gene expression of FXR and induces its translocation to the nucleus of MDA-MB-231 cells. Nuclear translocation of FXR is concurrent with the increase of urokinase-type plasminogen activator (uPA) and the formation of F-actin, two factors critical for the migration of breast cancer cells. Our results suggest a novel mechanism by which DC-induced increase of uPA and binding to the uPA receptor of the same breast cancer cell self-propel its migration and metastasis to the bone.

Investigation of the Drying Conditions for Amidosulfuric Acid

The drying conditions for primary standards of volumetric analysis have a significant effect on the titration results due to changes in the purity, stability and homogeneity. Amidosulfuric acid, a strong acid used as a reference material for volumetric analysis in Japan, was dried in a vacuum desiccator or heated at different temperatures, and then measured by Karl-Fischer titration, thermogravimetry/mass spectroscopy (TG-MS), ion chromatography and coulometric titration. The optimum drying conditions were at 50 degrees C for 24 h with crushing.

Enhancement of tissue engineered bone formation by a low pressure system improving cell seeding and medium perfusion into a porous scaffold

To obtain more extensive bone formation in composites of porous ceramics and bone marrow stromal cells (BMSCs), we hypothesized that a low-pressure system would serve to facilitate the perfusion of larger number of BMSCs into the porous scaffold, enhancing bone formation within the composites. After culturing BMSCs in osteogenic medium, porous blocks of β-tricalcium phosphate (β-TCP) were soaked in the cell suspension. Composites of the block and BMSCs were put immediately into a vacuum desiccator. Low pressure was applied to the low pressure group, while controls were left at atmospheric pressure. Composites were incubated in vitro or subcutaneously implanted into syngeneic rats, then analyzed biologically and histologically. In the in vitro group, cell suspension volume, cell seeding efficiency, alkaline phosphatase (ALP) activity, and DNA content in the β-TCP blocks were significantly higher in low pressure group than in the controls. Scanning electron microscopy (SEM) demonstrated that a greater number of cells covered the central parts of the composites in the low pressure group. ALP activity in the composites was increased at 3 and 6 weeks after implantation into rats. Histomorphometric analysis revealed more uniform and extensive bone formation in the low pressure group than in the controls. The application of low pressure during the seeding of BMSCs in perfusing medium into a porous scaffold is useful for tissue-engineered bone formation.

Adsorption of Nitrogen, Oxygen, and Argon in Cobalt(II)-Exchanged Zeolite X

Adsorption of nitrogen, oxygen, and argon on cobalt(II)-exchanged zeolite X at 288.2 and 303.0 K was studied. The nitrogen and oxygen adsorption capacities increase upon cobalt ion exchange up to 71%, beyond which it shows a decreasing trend because of the partial degradation of the zeolite structure during the cation exchange and high-temperature vacuum dehydration processes. The magnitude of the increase in the adsorption capacities for nitrogen is much higher than that of oxygen. The nitrogen/oxygen as well as nitrogen/argon selectivities in the low-pressure region increase with an increase in cobalt exchange. Marginal oxygen selectivity over argon is observed for zeolite samples with higher cobalt exchange. The heats of adsorption values for nitrogen and oxygen increase and that for argon remain unaffected by cobalt exchange in zeolite X. The very high nitrogen adsorption capacity, selectivity, and heat of adsorption in the low-pressure region for cobalt-exchanged zeolite X compared to the parent sodium form of the zeolite show stronger interaction between nitrogen molecules with the extraframework cobalt cations of the zeolite. This stronger interaction has been explained in terms of the pi-complexation between nitrogen molecules and cobalt cations of the zeolites, as confirmed by diffuse reflectance infrared Fourier transform spectroscopy, wherein the N[triple bond]N stretching frequency at 2099 cm(-1) is observed for N2 molecules adsorbed in NaCoX.

Single crystal structure of fully dehydrated, excessively Cd 2+-exchanged zeolite Y, ∣Cd 27.5(Cd 8O 4) 2∣[Si 121Al 71O 384]-FAU, containing [formula omitted] clusters

The structure of fully dehydrated, excessively Cd 2+-exchanged zeolite Y, ∣Cd 27.5(Cd 8O 4) 2∣[Si 121Al 71O 384]-FAU, has been determined using single-crystal X-ray diffraction techniques in the cubic space group Fd 3 ¯ m at 21(1) °C. Ion exchange was accomplished by allowing an aqueous stream 0.05 M in Cd 2+, pH 7, to flow past the crystal for 5 days. The crystal was then dehydrated at 350 °C and 2 × 10 −6 Torr for 2 days. The structure was determined in vacuum and was refined using all 690 unique reflections to the final error indices (based only upon the 357 reflections for which F o > 4 σ( F o)), R 1 = 0.060 and wR 2 = 0.151. In this structure, Cd 2+ ions occupy five crystallographic sites. Eight Cd 2+ ions half fill site I at the centers of the double six-rings (Cd–O (octahedral) = 2.498(11) Å), eight Cd 2+ ions one-quarter fill a site-I′ position deep in the sodalite cavities (Cd–O (octahedral) = 2.559(17) Å) and another eight one-quarter fill a more conventional site-I′ position (Cd–O = 2.278(14) Å), eight Cd 2+ ions one-quarter fill site II′ inside the sodalite cavities (Cd–O = 2.192(11) Å), and the remaining 11.5 Cd 2+ ions are found at site II in the supercages (Cd–O = 2.179(9) Å). The Cd 2+ ions at the first I′ position form, with non-framework oxide ions, Cd 4O 4 clusters (interpenetrating tetrahedra, symmetry 4 ¯ 3 m ( T d ) , Cd–O = 2.33(4) Å) in two of the eight sodalite cavities per unit cell. Each Cd 4O 4 unit coordinates further via its oxygen atoms to four more Cd 2+ ions at site II′, Cd–O = 1.86(11) Å, to give the larger cationic Cd 8 O 4 8 + clusters (symmetry still 4 ¯ 3 m ( T d ) ) . During ion exchange at pH 7, zeolite Y had apparently imbibed eight Cd(OH) 2 molecules per unit cell; these decomposed upon vacuum dehydration to give, with eight additional Cd 2+ ions, two Cd 8 O 4 8 + clusters.

Crystal Structure of an Ethylene Sorption Complex of Fully Vacuum-Dehydrated Fully Ag+-Exchanged Zeolite X (FAU). Silver Atoms Have Reduced Ethylene To Give CH22- Carbanions at Framework Oxide Vacancies

The crystal structure of an ethylene sorption complex of fully vacuum-dehydrated fully Ag(+)-exchanged zeolite X (FAU), a = 24.865(2) A, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd at 21 degrees C. It is very different from the ethylene complex of Ag(92)-X that had been dehydrated at 400 degrees C in flowing oxygen, as were the two dehydrated structures. The crystal was prepared by ion exchange in a flowing stream of aqueous 0.05 M AgNO(3) for 3 days, followed by dehydration at 400 degrees C and 2 x 10(-6) Torr for 2 days, followed by exposure to 300 Torr of zeolitically dry ethylene gas for 2 h at 21 degrees C. The structure was determined in this atmosphere and was refined using all data to the final error indices (based upon the 534 reflections for which F(o) > 4sigma(F(o))) R(1) = 0.062 and wR(2) = 0.135. In this structure, per unit cell, 14 Ag(+) ions were found at the octahedral site I (Ag-O = 2.611(9) A), and 32 partially reduced Ag(+) ions fill two different site I' positions deep in the sodalite cavities (Ag-O = 2.601(13) and 2.618(12) A). The sodalite cavities host two different cationic silver clusters. In about 47% of sodalite units, eight silver atoms form interpenetrating tetrahedra, Ag(8)(n+) (n = 4 is suggested), with T(d)() symmetry. The other 53% of the sodalite units host cyclo-Ag(4)(m+) (m = 2 is suggested) cations with near S(4) symmetry. These clusters are very similar to those in vacuum-dehydrated Ag(92)-X. Thirty-two Ag(+) ions fill the single 6-rings, 15 at site II' (Ag-O = 2.492(10) A), and 17 at site II (Ag-O = 2.460(9) A). The latter 17 lie in supercages where each forms a lateral pi-complex with an ethylene molecule. In turn, each C(2)H(4) molecule forms two cis electrostatic hydrogen bonds to framework oxygens. The remaining 14 Ag+ ions occupy three different II' sites. Vacuum dehydration had caused substantial decomposition: per unit cell, 30 of the 92 Ag(+) ions were reduced and 15 of the 384 framework oxide ions were oxidized to O2(g), leaving lattice vacancies. The sorption of C(2)H(4) at 21 degrees C reoxidized about 7 of the 30 Ag(0) atoms to Ag(+) and reduced 1.75 ethylene molecules to give CH(2)(2-) groups which refilled 3.5 of these 15 lattice vacancies. The remaining vacancies may have been filled with H(2)C=C(2-) ions. The unit cell formula, which originally contained 384 oxygen atoms, may be |Ag(92)(C2H4)17|[Si(100)Al(92)O(369)(CH2)3.5] or |Ag(92)H(23)(C2H4)17|[Si(100)Al(92)O(369)(CH2)3.5(C2H2)11.5].