SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
AuCl4 is diamond structured and crystallizes in the tetragonal I4_1/amd space group. The structure is zero-dimensional and consists of four AuCl4 clusters. Au is bonded in a rectangular see-saw-like geometry to four equivalent Cl atoms. All Au–Cl bond lengths are 2.30 Å. Cl is bonded in a single-bond geometry to one Au atom.
AuCl4(NS)5 crystallizes in the monoclinic P2_1/m space group. The structure is zero-dimensional and consists of two AuCl4 clusters and two NS clusters. In each AuCl4 cluster, Au5+ is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. All Au–Cl bond lengths are 2.32 Å. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Au5+ atom. In the second Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Au5+ atom. In each NS cluster, there are three inequivalent N+1.80+ sites. In the first N+1.80+ site, N+1.80+ is bonded in a bent 150 degrees geometry to two S2- atoms. Both N–S bond lengths are 1.58 Å. In the second N+1.80+ site, N+1.80+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.56 Å) and one longer (1.57 Å) N–S bond length. In the third N+1.80+ site, N+1.80+ is bonded in a distorted bent 150 degrees geometry to two equivalent S2- atoms. Both N–S bond lengths are 1.59 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a bent 120 degrees geometry to two equivalent N+1.80+ atoms. In the second S2- site, S2- is bonded in a water-like geometry to two N+1.80+ atoms. In the third S2- site, S2- is bonded in a water-like geometry to two N+1.80+ atoms.
(AuCl4)2N2 is Tungsten Carbide-like structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four ammonia molecules and four AuCl4 clusters. In each AuCl4 cluster, Au1- is bonded in a square co-planar geometry to four Cl1- atoms. All Au–Cl bond lengths are 2.30 Å. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1- atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1- atom.
AuCl4(H2O)2H5O2 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one molecular hydrogen;dihydrate molecule, two water molecules, and one AuCl4 cluster. In the AuCl4 cluster, Au3+ is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. There are one shorter (2.31 Å) and three longer (2.32 Å) Au–Cl bond lengths. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom.
(AuCl4)2(O2)3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four trioxidane molecules and four AuCl4 clusters. In each AuCl4 cluster, Au is bonded in a rectangular see-saw-like geometry to four Cl atoms. There are a spread of Au–Cl bond distances ranging from 2.29–2.33 Å. There are four inequivalent Cl sites. In the first Cl site, Cl is bonded in a single-bond geometry to one Au atom. In the second Cl site, Cl is bonded in a single-bond geometry to one Au atom. In the third Cl site, Cl is bonded in a single-bond geometry to one Au atom. In the fourth Cl site, Cl is bonded in a single-bond geometry to one Au atom.
(AuCl4)4(AuN2(OCl2)2)2N2 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four ammonia molecules, eight AuCl4 clusters, and four AuN2(OCl2)2 clusters. In each AuCl4 cluster, Au3+ is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. There are a spread of Au–Cl bond distances ranging from 2.30–2.34 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the fourth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Au3+ atom. In each AuN2(OCl2)2 cluster, Au3+ is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. All Au–Cl bond lengths are 2.31 Å. N+2.33+ is bonded in a distorted single-bond geometry to one O2- and one Cl1- atom. The N–O bond length is 1.13 Å. The N–Cl bond length is 2.48 Å. O2- is bonded in a single-bond geometry to one N+2.33+ atom. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one Au3+ and one N+2.33+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom.
AuCl4PCl4 is alpha iridium vanadium structured and crystallizes in the orthorhombic Imma space group. The structure is zero-dimensional and consists of eight [pcl4]+1 molecules and eight AuCl4 clusters. In each AuCl4 cluster, Au3+ is bonded in a square co-planar geometry to four Cl1- atoms. There are three shorter (2.32 Å) and one longer (2.33 Å) Au–Cl bond lengths. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom.
AuCl4SCl3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four AuCl4 clusters and four SCl3 clusters. In each AuCl4 cluster, Au1+ is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. There are a spread of Au–Cl bond distances ranging from 2.31–2.34 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1+ atom. In each SCl3 cluster, S6+ is bonded in a trigonal non-coplanar geometry to three Cl1- atoms. There are two shorter (2.03 Å) and one longer (2.04 Å) S–Cl bond lengths. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one S6+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one S6+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one S6+ atom.
AuCl4C5S4 crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of four 4,5-bis(methylsulfanyl)-1,3-dithiole molecules and four AuCl4 clusters. In each AuCl4 cluster, Au1- is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. There are a spread of Au–Cl bond distances ranging from 2.31–2.34 Å. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Au1- atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1- atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1- atom.
AuCl4CN3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four guanidine molecules and four AuCl4 clusters. In each AuCl4 cluster, Au1+ is bonded in a square co-planar geometry to four Cl1- atoms. All Au–Cl bond lengths are 2.30 Å. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Au1+ atom.
AuCl4Au2N(OCl4)2N2 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of eight ammonia molecules, four Au2N(OCl4)2 clusters, and four AuCl4 clusters. In each Au2N(OCl4)2 cluster, Au3+ is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. There are a spread of Au–Cl bond distances ranging from 2.30–2.43 Å. N+2.33+ is bonded in a linear geometry to two equivalent Cl1- atoms. Both N–Cl bond lengths are 2.08 Å. O2- is bonded in a single-bond geometry to one Cl1- atom. The O–Cl bond length is 1.53 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted bent 120 degrees geometry to one Au3+ and one N+2.33+ atom. In the second Cl1- site, Cl1- is bonded in a distorted bent 120 degrees geometry to one Au3+ and one O2- atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In each AuCl4 cluster, Au3+ is bonded in a square co-planar geometry to four Cl1- atoms. There are two shorter (2.30 Å) and two longer (2.31 Å) Au–Cl bond lengths. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Au3+ atom. In the second Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Au3+ atom.
Bipolar membranes (BPMs) which consist of a cation exchange layer (CEL) and anion exchange layer (AEL) are quite effective as membranes in gas phase electrolyzers. However, such membranes can also serve as a host to embed photocatalysts and electrocatalysts. By selectively exchanging cations with Cd 2+ and anions with AuCl 4 – , we were able to synthesize CdS and Au nanoparticles in CEL and AEL layers, respectively, through sequential chemical and photocatalytic reactions. Reacting Cd 2+ with thioacetamide formed the CdS nanoparticles in CEL. The photogenerated electrons from CdS were then used to reduce AuCl4– in an H-cell configuration to produce Au nanoparticles in AEL and thus prepare a photocatalytically active BPM film (referred to as a CdS/BPM/Au film). Such a concerted design of BPM allows “vectorial” electron transfer between two layers of BPM leading to its transfer to an acceptor molecule (methyl viologen) in solution. Designing photocatalytically active BPM and understanding the vectorial electron flow between two separate ion-selective layers offer new opportunities in water splitting and CO 2 reduction.
AuCl is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Au1+ is bonded to four equivalent Cl1- atoms to form corner-sharing AuCl4 tetrahedra. All Au–Cl bond lengths are 2.61 Å. Cl1- is bonded to four equivalent Au1+ atoms to form corner-sharing ClAu4 tetrahedra.
The relatively recent decrease in the acceptable time-weighted-average for hydrazines from 100 parts-per-billion (ppb) to 10 ppb rendered many trace hydrazine detectors either insensitive or inaccurate. Development of a rapid detection method for hydrazines at the new 10-ppb concentration was necessary so that test area personnel could reliably assess airborne hydrazines concentrations of a potentially contaminated area prior to entry. The reduction of Au(III) to Au(0) by hydrazines is a well characterized reaction and application of the corresponding yellow to purple color change was selected as a potentially useful means for detection of trace hydrazines in air. Tests with small quantities of KAuCl4 deposited on a variety of substrates were conducted using verified sources of 1,1-dimethylhydrazine, methylhydrazine, and hydrazine at approximately 10 ppb in air. Substrates tested were glass fiber filter paper, glass beads, anion exchange resin (AuCl4- form), and diatomaceous earth. The most successful of these substrates were glass fiber filter paper and diatomaceous earth. The KAuC14 impregnated glass fiber filter paper appeared to be somewhat light sensitive so further tests were conducted using the diatomaceous earth substrate. KAuCl4 concentration, substrate particle size, and sampler configuration were evaluated. Based on these tests, the device selected for further evaluation was a 5mm OD by 50mm glass tube containing 0.02-0.03g of 45/60 mesh diatomaceous earth coated with 2 percent KAuCl4. When connected to a sampling pump, response of the device to changes in relative humidity, ambient light, and high levels of other fluids, which might also be found in a propellant test area, was evaluated. False positive responses were not detected for exposures to relative humidity changes from 10 to 80 percent, sunlight for greater than 10 minutes, or percent levels of ammonia, isopropyl alcohol, nitrogen dioxide, and hydrogen. In addition, body emissions did not produce a false positive response in view of potential application for use inside protective clothing. The device was shown to reliably detect less than 10 ppb of the hydrazines tested using a 10 to 20L sample followed by a 2 to 5 minute color development time. Some field tests were conducted in parallel with conventional acidic firebrick sorbent tubes. There was generally very good agreement between the devices and firebrick sorbent tubes when greater than 10 ppb of a hydrazine was present.