bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platinum(II) Mixed Ligand Complexes with Thiourea Derivatives, Dimethyl Sulphoxide and Chloride: Syntheses, Molecular Structures, and ESCA Data
Authors: Hernández Wilfredo , Spodine Evgenia , Richter Rainer , Hallmeier Karl‐Heinz , Schröder Uwe , Beyer Lothar 
Published: December 2003

AbstractThe platinum(II) mixed ligand complexes [PtCl(L1‐6)(dmso)] with six differently substituted thiourea derivatives HL, R2NC(S)NHC(O)R′ (R = Et, R′ = p‐O2N‐Ph: HL1; R = Ph, R′ = p‐O2N‐Ph: HL2; R = R′ = Ph: HL3; R = Et, R′ = o‐Cl‐Ph: HL4; R2N = EtOC(O)N(CH2CH2)2N, R′ = Ph: HL5) and Et2NC(S)N=CNH‐1‐Naph (HL6), as well as the bis(benzoylthioureato‐κO, κS)‐platinum(II) complexes [Pt(L1, 2)2] have been synthesized and characterized by elemental analysis, IR, FAB(+)‐MS, 1H‐NMR, 13C‐NMR, as well as X‐ray structure analysis ([PtCl(L1)(dmso)] and [PtCl(L3, 4)(dmso)]) and ESCA ([PtCl(L1, 2)(dmso)] and [Pt(L1, 2)2]). The mixed ligand complexes [PtCl(L)(dmso)] have a nearly square‐planar coordination at the platinum atoms. After deprotonation, the thiourea derivatives coordinate bidentately via O and S, DMSO bonds monodentately to the PtII atom via S atom in a cis arrangement with respect to the thiocarbonyl sulphur atom. The Pt—S‐bonds to the DMSO are significant shorter than those to the thiocarbonyl‐S atom. In comparison with the unsubstituted case, electron withdrawing substituents at the phenyl group of the benzoyl moiety of the thioureate (p‐NO2, o‐Cl) cause a significant elongation of the Pt—S(dmso)‐bond trans arranged to the benzoyl‐O—Pt‐bond. The ESCA data confirm the found coordination and bonding conditions. The Pt 4f7/2 electron binding energies of the complexes [PtCl(L1, 2)(dmso)] are higher than those of the bis(benzoylthioureato)‐complexes [Pt(L1, 2)2]. This may indicate a withdrawal of electron density from platinum(II) caused by the DMSO ligands.
1:1 Adducts of Copper(I) and Silver(I) Halides with the Olefinic Phosphane Tri(1‐cyclohepta‐2, 4, 6‐trienyl)phosphane. Molecular Structures of CuX[P(C7H7)3] (X = Cl, Br), AgCl[P(C7H7)3] and {Cu(μ3‐I)[P(C7H7)3]}4
Authors: Herberhold Max , Akkus Nilgün , Milius Wolfgang 
Published: December 2003

AbstractA suspension of CuX (X = Cl, Br) or AgCl in organic solvents (such as CH2Cl2) reacts with P(C7H7)3 (1) in a molar ratio 1:1 to give the mononuclear adducts CuX[P(C7H7)3] (X = Cl (2a), Br (2b)) and AgCl[P(C7H7)3] (3a) which crystallize as isotypic compounds in the orthorhombic space group Pnma (Z = 4). In the crystal, two (of the three) cyclohepta‐2, 4, 6‐trienyl substituents are present in the boat conformation, thus establishing a loose long‐distance interaction between the central double bond and the metal atom. A distorted pseudo‐tetrahedral coordination sphere is assumed to exist around the metal atom, with large P‐M‐X angles of 165.49(8)° (2a), 162.07(7)° (2b) and 168.54(3)° (3a), respectively. The tetrameric 1:1 adduct {Cu(μ3‐I)[P(C7H7)3]}4(2c) which was obtained from CuI and 1 in boiling ethanol, has also been characterized by X‐ray crystallography (monoclinic space group P2(1)/n, Z = 4); it contains all 12 cyclohepta‐2, 4, 6‐trienyl substituents in the chair conformation.The NMR spectra (1H, 13C, 31P) of the new complexes 2a‐c and 3a indicate non‐rigid structures in solution. At room temperature, the 31P NMR signal of 3a appears as a doublet with an averaged coupling constant, 1J(Ag, P), of 700.1 Hz, whereas at —45 °C the two expected doublets are clearly discernible with coupling constants 1J(107Ag, 31P) = 671.0 Hz and 1J(109Ag, 31P) = 774.4 Hz, respectively.
Syntheses and Structures of two 1‐D Complexes, [Co(dmf)2(NCNCN)2] and [Cu(bipy)(NCNCN)]ClO4 with Bridging Dicyanamide Ligands
Authors: Dong Wen , Liang Mao , Sun Ya‐Qiu , Liu Zhan‐Quan 
Published: December 2003

AbstractTwo novel dicyanamide complexes [Co(dmf)2(NCNCN)2] (1) and [Cu(bipy)(NCNCN)]ClO4 (2) have been synthesized and structurally characterized. 1 crystallizes in the monoclinic space group C2 with a = 13.568(6)Å, b = 7.403(3)Å, c = 8.118(3)Å and Z = 2, whereas 2 crystallizes in the monoclinic system, Cc group, a = 14.270(7)Å, b = 9.143(5)Å, c = 12.371(1) Å, β = 118.612(7)°, and Z = 4. According to X‐ray crystallographic studies, in complex 1 each CoII ion is six‐coordinated with four nitrogen atoms from four μ1, 5‐dca (dca = dicyanamide) ligands and two oxygen atoms from two dmf ligands to form distorted octahedra. 1 forms a 1‐D network bridged via μ1, 5‐dca. 2 consists of a uniform Cu(NCNCN)Cu chain, each CuII ion is octahedrally coordinated with four nitrogen atoms from two μ1, 5‐dca ligands and one bipy ligand and two oxygen atoms from two ClO4— ions. The octahedral CuII ion shows a significant Jahn‐Teller distortion, with two axial oxygen atoms considerably farther from the copper than the four equatorial nitrogens.
Polysulfonylamine. CLXVI [1] Kristallstrukturen von Metall‐di(methansulfonyl)amiden. 15 [1] Die isotypen Kristallstrukturen von Ammonium‐ und Caesium‐dimesylamid: Kristallographische Kongruenz zwischen Wasserstoffbrücken N—H···O/N und Metall‐Ligand‐Bindungen Cs—O/N
Authors: Zerbe Eva‐Maria , Jones Peter G. , Moers Oliver , Blaschette Armand 
Published: December 2003

AbstractDas Ammoniumsalz NH4[N(SO2CH3)2] ist isostrukturell zur früher beschriebenen Caesiumverbindung Cs[N(SO2CH3)2] (monoklin, Raumgruppe P21/n, Z = 4, V bei —140 °C: 0, 761 bzw. 0, 832 nm3). Das Caesiumion erreicht eine unregelmäßige (O6N)‐Heptakoordination durch Wechselwirkungen mit einem (O, N)‐ und einem (O, O)‐chelatisierenden sowie drei κ1O‐bindenden Anionen, während in der Struktur des Ammoniumsalzes jede der sieben (Cs—O/N)‐Bindungen perfekt von einer (N—H···O/N)‐Wasserstoffbrückenkomponente nachgeahmt wird. Zu diesem Zweck bilden drei N—H‐Donoren asymmetrische Dreizentrenbrücken, der vierte eine mittelstarke und annähernd lineare Zweizentrenbrücke. In den Kristallpackungen existieren zickzackförmige planare Kationreihen, die sich über Symmetriezentren fortpflanzen (Cs···Cs alternierend 422, 5 und 487, 5 pm, Cs···Cs···Cs 135, 7°; N···N alternierend 397, 4 und 474, 1 pm, N···N···N 136, 1°); die Kationreihen sind zwischen Anion‐Monoschichten in der Weise intercaliert, daß jede von vier translationsgenerierten Anionstapeln umgeben und gebunden wird und jeder Anionstapel zwei Kationreihen miteinander verknüpft. Im Endeffekt resultiert für die Caesiumverbindung ein dreidimensionales Netzwerk von Metall‐Ligand‐Bindungen, für das Ammoniumsalz ein damit kongruentes Netzwerk von Wasserstoffbrücken. Außerdem treten in beiden Strukturen schwache interanionische Wasserstoffbrücken des Typs C—H···O/N auf.
Surface Termination and Thermal Elimination Behaviour of Activated Hydrogenated Germanium
Authors: Schlecht Sabine , Himmel Hans‐Jörg 
Published: December 2003

AbstractActivated hydrogenated germanium that shows a high chemical reactivity for insertion into various non‐metal/non‐metal bonds, was investigated by surface IR spectroscopy with respect to its surface properties and potential elimination reactions at the surface. Spectroscopic and kinetic data stongly suggest that the high reactivity is due to intrinsic defects and dangling bonds in the amorphous network and does not stem from an elimination step prior to the insertion of the activated germanium. Further investigations support our former description of activated germanium as a low‐valent germanium hydride with a minor content of chloride. In addition, small amounts of coordinated 1, 4‐dioxane can be found on the surface.
Synthesis and Crystal Structure of [Fe(Cp)2]3(Bi2Cl9)·thf
Authors: Savilov Serguei , Kloo Lars , Kuznetsov Alexei , Popovkin Boris , Fischer Andreas 
Published: December 2003

AbstractSingle crystals of [Fe(Cp)2]3(Bi2Cl9)·thf were obtained from a thf solution containing ferrocene and BiCl3. The structure shows disorder at room temperature which disappears upon cooling, coupled with a decrease in symmetry. The title compound crystallizes in the orthorhombic space group P212121 [a = 1698.64(2), b = 2318.69(3), c = 1085.66(2) pm] with three ferrocenium ions, one nonachlorodibismutate ion and one molecule of thf in the asymmetric unit.
Cyclooctatetraenyl Complexes of the Early Transition Metals and Lanthanides. 13. [1] The First Organolanthanide Complex of the Tripod Ligand [(C5H5)Co{P(O)(OEt)2}3]—
Authors: Reißmann Ulrike , Edelmann Frank T. 
Published: December 2003

AbstractThe reaction of [(η8‐C8H8)Sm(μ‐Cl)(THF)]2 (1) with Na[(C5H5)Co{P(O)(OEt)2}3] (2) in a molar ratio of 1:2 in THF solution affords orange, crystalline (η8‐C8H8)Sm[(C5H5)Co{P(O)(OEt)2}3] (3) as the first organolanthanide complex containing Kläui' tripod ligand. The compound has been fully characterized by elemental analysis and spectroscopic methods.
Anhydrous Mercurous Chlorate, Hg2(ClO3)2
Authors: Göbbels Dirk , Meyer Gerd 
Published: December 2003

AbstractColourless single crystals of the anhydrous mercurous chlorate were grown from a solution of mercuric oxide (HgO) in chloric acid (HClO3) in the presence of elemental mercury. The crystal structure (monoclinic, P21/n, Z = 4, a = 816.59(12), b = 641.02(5), c = 1290.3(2) pm, β = 97.506(12)°, R(all) = 0.0317) contains trans‐O2ClO‐Hg‐Hg‐OClO2 molecules with a Hg‐Hg distance of 251.03(4) pm, Hg‐O (bond) distances of 218 and 224 pm and Hg‐Hg‐O angles of 177 and 165°, respectively.
Synthesis and Crystal Structure of a new O, N Lithium Coordination Polymer
Authors: Ghassemzadeh Mitra , Heravi Majid M. , Hekmat‐Shoar Rahim , Neumüller Bernhard 
Published: December 2003

AbstractThe reaction of 4‐Amino‐6‐methyl‐1, 2, 4‐triazine‐3(2H)‐thione‐5‐one (HAMTTO) with n‐butyl lithium in dimethoxyethane (DME) gives the complex [Li(DME)(AMTTO)] (1). 1 was characterized by elemental analysis, IR‐ and mass‐spectrometry and an X‐ray structure analysis [space group P21/n, Z = 4, lattice dimensions at —80 °C: a = 867.6(1), b = 1721.5(2), c = 931.8(1) pm, β = 112.81(1)°, R1 = 0.0315. The complex is a coordination polymer along [001] with a zig‐zag arrangement.
Neue neutrale und kationische Mono‐Aziridin‐Komplexe des Typs [CpMn(CO)2Az], [CpCr(NO)2Az]+ und [(Ph3P)(CO)4ReAz]+ über CO‐, Hydrid‐ und Chlorid‐Abspaltungsreaktionen
Authors: Wilberger Roland , Piotrowski Holger , Warchhold Marcus , Lorenz Ingo‐Peter 
Published: December 2003

AbstractDie Mono‐Aziridin‐Komplexe 1—5 werden nach drei unterschiedlich induzierten Substitutionsreaktionen hergestellt. Bei der photolytischen CO‐Abspaltung von [CpMn(CO)3] in Gegenwart von 2, 2‐Dimethylaziridin entsteht der neutrale Aziridin‐N‐Komplex [Cp(CO)2Mn{$\overline{N(H)CMe2C}$H2}] (1). Durch Hydrid‐Abspaltung von [(Ph3P)(CO)4ReH] mit CF3SO3H und nachfolgende Behandlung mit 2, 2‐Dimethylbzw. 2‐Ethyl‐aziridin lassen sich die salzartigen Aziridin‐Komplexe [(Ph3P)(CO)4Re{$\overline{N(H)CMe2C}$H2}](CF3SO3) (2) bzw. [(Ph3P)(CO)4Re{$\overline{N (H)CHEtC}$H2}](CF3SO3) (3) gewinnen. Die ebenfalls salzartigen Komplexe [Cp(NO)2Cr{$\overline{N(H)CMe2C}$H2}](BF4) (4) und [Cp(NO)2RCr{$\overline{N(H)CHEtC}$H2}](CF3SO3 (5) werden nach Chlorid‐Abstraktion aus [CpCr(NO)2Cl] mit AgX (X = BF4, CF3SO3) in Gegenwart von 2, 2‐Dimethyl‐ bzw. 2‐Ethylaziridin hergestellt. Den Röntgenstrukturanalysen zufolge sind die Metallatome trigonal pyramidal (1, 4, 5) bzw. oktaedrisch (cis‐Position, 2, 3) konfiguriert; die intakten Dreiringe sind über die verzerrt tetraedrisch konfigurierten N‐Atome gebunden. Verbindungen 1—5 sind hinsichtlich einer gezielten Alken‐Abspaltung unter Bildung von Nitren‐Komplexen stabil; ihre IR, 1H‐ und 13C{1H}‐NMR‐ und MS‐Spektren werden vorgestellt und diskutiert.
Darstellung, spektroskopische Charakterisierung und Normalkoordinatenanalyse der bindungsisomeren Tetrachloroiodoselenocyanatoosmate(IV). Kristallstruktur von trans‐(PPh4)2[OsCl4I(NCSe)]
Authors: Dallmann K. , Rehbehn S. , Preetz W. 
Published: December 2003

AbstractBei der Umsetzung einer Lösung von (n‐Bu4N)2[OsCl5I] in Dichlormethan mit darin suspendiertem Pb(SeCN)2 entstehen die Bindungsisomeren trans‐(n‐Bu4N)2[OsCl4I(NCSe)] (1) und trans‐(n‐Bu4N)2[OsCl4I(SeCN)] (2), die durch Ionenaustauschchromatographie an Diethylaminoethyl‐Cellulose getrennt werden. Die Röntgenstrukturanalyse an einem Einkristall von trans‐(PPh4)2[OsCl4I(NCSe)] (triklin, Raumgruppe P1¯, a = 10, 8950(13), b = 11, 076(2), c = 20, 980(2)Å, α = 96, 940(10), β = 98, 747(9), γ = 104, 419(11)°, Z = 2) zeigt, daß die annähernd lineare, zum Iodatom trans‐ständige Selenocyanatgruppe unter dem Os‐N‐C‐Winkel von 171, 1° koordiniert ist. Unter Verwendung der röntgenographisch bestimmten (1) und abgeschätzten (2) Molekülparameter lassen sich die IR‐ und Raman‐Spektren der beiden Bindungsisomeren durch Normalkoordinatenanalysen zuordnen. Die Valenzkraftkonstanten betragen fd(OsN) = 1, 70 und fd(OsSe) = 1, 15 mdyn/Å.
The causal ordering of mathematics anxiety and mathematics achievement: a longitudinal panel analysis
Authors: Ma X , Xu Jiangming 
Published: December 2003

AbstractUsing data from the Longitudinal Study of American Youth (LSAY), we aimed to determine the causal ordering between mathematics anxiety and mathematics achievement. Results of structural equation modelling showed that, across the entire junior and senior high school, prior low mathematics achievement significantly related to later high mathematics anxiety, but prior high mathematics anxiety hardly related to later low mathematics achievement. Mathematics achievement was more reliably stable from year to year than mathematics anxiety. There were statistically significant gender differences in the causal ordering between mathematics anxiety and mathematics achievement. Prior low mathematics achievement significantly related to later high mathematics anxiety for boys across the entire junior and senior high school but for girls at critical transition points only. Mathematics anxiety was more reliably stable from year to year among girls than among boys.
Unusual form of neurocysticercosis associated with HIV infection
Authors: Delobel P. , Signate A. , El Guedj M. , Couppie P. , Gueye M. , Smadja D. , Pradinaud R. 
Published: December 2003

Concurrent infection with Taenia solium and HIV would be expected to occur more frequently because of the increasing frequency of HIV infection in endemic areas of cysticercosis. However, little is known about the influence of HIV infection on the frequency and the clinical course of cysticercosis. Giant cysts and racemose forms of neurocysticercosis seem to be more frequent in HIV‐infected patients and may be secondary to an uncontrolled parasitic growth because of an impaired cell‐mediated immune response. We report an unusual case of epidural spinal racemose neurocysticercosis revealed by compression of cauda equina in an HIV‐infected man and discuss the potential interactions between T. solium and HIV infections.
Ion Implantation into Presolar Grains: A Theoretical Model
Authors: Verchovsky A. B. , Wright I. P. , Pillinger C. T. 
Published: December 2003

AbstractA numerical model for ion implantation into spherical grains in free space has been developed. It can be applied to single grains or collections of grains with known grain-size distributions. Ion-scattering effects were taken into account using results of computer simulations. Possible isotope and element fractionation of the implanted species was investigated using this model. The astrophysical significance of the model lies in the possible identification of energetically different components (such as noble gases) implanted into presolar grains (such as diamond and SiC) and in establishing implantation energies of the components.
Evolution of Rotating AGB Stars and the s-Process Nucleosynthesis
Authors: Siess Lionel , Goriely Stéphane , Langer Norbert 
Published: December 2003

AbstractWe present new results on the evolution and nucleosynthesis in rotating AGB stars. We analyse the role of the gradient of mean molecular weight in the mixing process and show that neglecting this component induces a potentially strong third dredge-up. We also quantify the impact of rotation on the structure and conclude that the effects of rotation (1) mainly concern the inner, fast rotating regions of the stars and (2) are relatively weak as long as rotational mixing does not induce a deep third dredge-up. We also focus our investigations on the s-process nucleosynthesis and show that rotational mixing tends to inhibit the production of s-elements. This results from the contamination of the 13C-rich layers responsible for the neutron production by the poisonous 14N. Our calculations also indicate that the distribution of s-process elements depends sensitively on the magnitude of the diffusion coefficient. These results suggest that rotational mixing is not the main mechanism responsible for the production of s-elements in AGB stars, but that it can influence, and in particular reduce, the final enrichment in s-elements.
Identification of Small Presolar Spinel and Corundum Grains by Isotopic Raster Imaging
Authors: Nguyen Ann , Zinner Ernst , Lewis Roy S. 
Published: December 2003

AbstractThe oxygen isotopic compositions of densely packed submicron oxide grains in two grain separates of different grain size from the CM2 carbonaceous chondrite Murray were determined by multi-detection raster imaging on the NanoSIMS ion microprobe. This led to the identification of 81 presolar spinel and 3 presolar corundum grains among ∼51 700 grains in the CF residue (mean diameter 0.15 µm) and 171 presolar spinel and 29 presolar corundum grains among ˜21 500 grains in the CG residue (mean diameter 0.45 µm). Previous NanoSIMS analysis of individual grains from the same residues has led to the discovery of 15 presolar spinel and 3 presolar corundum grains among 628 CF grains, and 9 presolar spinels among 753 CG grains. The oxygen isotopic compositions of the presolar oxides found by raster imaging are comparable to those of the presolar oxides measured individually. While the abundance of presolar spinel among the (larger) grains of the CG residue is the same for both techniques, the detection efficiency for presolar spinel by imaging among the (smaller) grains in CF is lower due to the small size of these grains. Nonetheless, it is possible to identify presolar grains of this size range. Though single grain measurements are effective for determining the precise isotopic compositions and abundances of presolar grains, raster ion imaging is the method of choice in searches for rare presolar grain types such as presolar silicates.
Short-Lived Nuclei in the Early Solar System: A Low Mass Stellar Source?
Authors: Busso M. , Gallino R. , Wasserburg G. J. 
Published: December 2003

AbstractWe discuss possible stellar origins of short-lived radioactive nuclei with meanlife τ ≤ 100 Myr, which were shown to be alive in the Early Solar System (ESS). We first review current ideas on the production of nuclides having 10 ≤ τ ≤ 100 Myr, which presumably derive from the continuous interplay of galactic astration, nucleosynthesis from massive supernovae and free decay in the interstellar medium. The abundance of the shorter lived 53Mn might be explained by this same scenario. Then we consider the nuclei 107Pd, 26Al, 41Ca and 60Fe, whose early solar system abundances are too high to have originated in this way. Present evidence favours a stellar origin, particularly for 107Pd, 26Al and 60Fe, rather than an in situ production by energetic solar particles. The idea of an encounter (rather close in time and space) between the forming Sun and a dying star is therefore discussed: this star may or may not have also triggered the solar formation. Recent nucleosynthesis calculations for the yields of the relevant short-lived isotopes and of their stable reference nuclei are discussed. Massive stars evolving to type II supernovae (either leaving a neutron star or a black hole as a remnant) seem incapable of explaining the four most critical ESS radioactivities in their observed abundance ratios. An asymptotic giant branch (AGB) star seems to be a viable source, especially if of relatively low initial mass (M ≤ 3 M⊙) and with low neutron exposure: this model can provide a solution for 26Al, 41Ca and 107Pd, with important contributions to 60Fe, which are inside the present uncertainty range of the 60Fe early solar system abundance. Such a model requires that 26Al is produced substantially on the AGB by cool bottom processing. The remaining inventory of short-lived species in the solar nebula would then be attributed to the continuous galactic processing, with the exception of 10Be, which must reflect production by later proton bombardment at a low level during early solar history.
Low-Mass AGB Stellar Models for 0.003 ≤Z≤ 0.02: Basic Formulae for Nucleosynthesis Calculations
Authors: Straniero O. , Domínguez I. , Cristallo S. , Gallino R. 
Published: December 2003

AbstractWe have extended our published set of low-mass AGB stellar modelsto lower metallicities. Different mass-loss rates have been explored. We provide interpolation formulae for the luminosity, effective temperature, core mass, mass of dredge up material and maximum temperature in the convective zone generated by thermal pulses. Finally, we discuss the resultant modification of these quantities when we use an appropriate treatment of the inward propagation of the convective instability, as caused by the steeprise in radiative opacity when the convective envelope penetratesthe H-depleted region.
The Chemical Evolution of Magnesium Isotopic Abundances in the Solar Neighbourhood
Authors: Fenner Y. , Gibson B. K. , Lee H.-c. , Karakas A. I. , Lattanzio J. C. , Chieffi A. , Limongi M. , Yong D. 
Published: December 2003

AbstractThe abundance of the neutron-rich magnesium isotopes observed in metal-poor stars is explained quantitatively with a chemical evolution model of the local Galaxy that considers — for the first time — the metallicity-dependent contribution from intermediate mass stars. Previous models that simulate the variation of Mg isotopic ratios with metallicity in the solar neighbourhood have attributed the production of 25Mg and 26Mg exclusively to hydrostatic burning in massive stars. These models match the data well for [Fe/H] > –1.0 but severely underestimate 25,26Mg/24Mg at lower metallicities. Earlier studies have noted that this discrepancy may indicate a significant role played by intermediate mass stars. Only recently have detailed calculations of intermediate mass stellar yields of 25Mg and 26Mg become available with which to test this hypothesis. In an extension of previous work, we present a model that successfully matches the Mg isotopic abundances in nearby Galactic disk stars through the incorporation of nucleosynthesis predictions of Mg isotopic production in asymptotic giant branch stars.
AGB Stars and the Observed Abundance of Neon in Planetary Nebulae
Authors: Karakas A. I. , Lattanzio J. C. 
Published: December 2003

AbstractAsymptotic giant branch stars are expected to produce 22Ne through the combined H and He burning that operates during their thermally pulsing evolution. However, observationally there is a fairly tight correlation between the O and Ne abundances as measured in planetary nebulae in various populations. In this paper we use recent detailed stellar evolutionary calculations for compositions appropriate to the Galaxy and the Large Magellanic Cloud, in an attempt to determine if the models are consistent with the observed abundances. We show that there is only a narrow range in stellar mass, about 2 to 4 M⊙ (lower for lower [Fe/H]) where 22Ne is produced in sufficient quantities to affect the total observed elemental neon abundance, which is mostly 20Ne. The models appear to be consistent with the observations, but a more thorough analysis is required.
‘Star Dust Memories’—A Brief History of the Murchison Carbonaceous Chondrite
Authors: Henry Dermot A. 
Published: December 2003

AbstractThe rare carbonaceous chondrite which fell around the township of Murchison in northern Victoria, Australia, in 1969 has probably been the subject of more scientific publications than any other meteorite. The discovery of grains formed in a presolar environment and the abundance of organic molecules within the Murchison meteorite have facilitated studies of the formation of the Solar System, the development of stars and the origins of life.