bluuebunny/crossref_metadata_2025_split huggingface dataset:
Are Commercial Ceilings Appropriate for the Regulation of Free-to-Air TV Channels?
Authors: Rothbauer Julia , Sieg Gernot 
Published: February 2015

Abstract
Commercial ceilings not only restrict broadcasters in their decisions about commercial broadcasting time, but also affect their differentiation of program content. This study examines the welfare effects of commercial ceilings in a two-sided free-to-air TV market, taking into account welfare with respect to content differentiation. We identify a second-best commercial ceiling that maximizes welfare in the absence of enforceable program content regulation and identify the situations in which laissez faire is optimal. The deregulation of commercial broadcasting can improve welfare, even if the laissez-faire level of commercial broadcasting time is excessive.
Risk Aversion and Social Networks
Authors: Kovářík Jaromír , van der Leij Marco J. 
Published: February 2015

AbstractThis paper first investigates empirically the relationship between risk aversion and social network structure in a large group of undergraduate students. We find that risk aversion is strongly correlated to local network clustering, that is, the probability that one has a social tie to friends of friends. We then propose a network formation model that generates this empirical finding, suggesting that locally superior information on benefits makes it more attractive for risk averse individuals to link to friends of friends. Finally, we discuss implications of this model. The model generates a positive correlation between local network clustering and benefits, even if benefits are distributed independently ex ante. This provides an alternative explanation of this relationship to the one given by the social capital literature. We also establish a linkage between the uncertainty of the environment and the network structure: risky environments generate more clustered and more unequal networks in terms of connectivity.
Inferring bi-directional interactions between circadian clock genes and metabolism with model ensembles
Authors: Grzegorczyk Marco , Aderhold Andrej , Husmeier Dirk 
Published: February 2015

AbstractThere has been much interest in reconstructing bi-directional regulatory networks linking the circadian clock to metabolism in plants. A variety of reverse engineering methods from machine learning and computational statistics have been proposed and evaluated. The emphasis of the present paper is on combining models in a model ensemble to boost the network reconstruction accuracy, and to explore various model combination strategies to maximize the improvement. Our results demonstrate that a rich ensemble of predictors outperforms the best individual model, even if the ensemble includes poor predictors with inferior individual reconstruction accuracy. For our application to metabolomic and transcriptomic time series from various mutagenesis plants grown in different light-dark cycles we also show how to determine the optimal time lag between interactions, and we identify significant interactions with a randomization test. Our study predicts new statistically significant interactions between circadian clock genes and metabolites in
Synthesis, Crystal Structure, Spectroscopic and Thermal Properties of a Novel Mixed Ligand Copper(II) Complex with 5,5-Dimethylhydantoin and Benzylamine
Authors: Taş Murat , Soylu Serkan , Batı Hümeyra 
Published: February 2015

Abstract
The crystal structure of the newly synthesized complex, trans-aqua-bis(benzylamino)-bis(5,5-dimethylhydantoinato) copper(II) was determined by X-Ray single crystal data. The thermal analyses, FT-IR and magnetic susceptibility data are also presented. The complex crystallizes in the monoclinic system, space group C2. The complex features a distorted square pyramidal [CuN4O] coordination with 5,5-dimethylhydantoinato, benzylamine and water ligands. The 5,5-dimethylhydantoinato anion is bonded to the copper(II) ion via its deprotonated N atom in the 3-position.
Ferromagnetic Ordering in the Thallide EuPdTl2
Authors: Kraft Rainer , Rayaprol Sudhindra , Sebastian C. Peter , Pöttgen Rainer 
Published: February 2015

Abstract
The new thallide EuPdTl2, synthesized from the elements in a sealed tantalum tube in a highfrequency furnace, was investigated by X-ray diffraction on powders and single crystals: MgCuAl2 type, Cmcm, Z = 4, a = 446.6(1), b = 1076.7(2), c = 812.0(2) pm, wR2 = 0.0632, 336 F2 values, 16 variables. The structure can be considered as an orthorhombically distorted, palladium-filled variant of the binary Zintl phase EuTl2. The palladium and thallium atoms build up a three-dimensional [PdTl2] polyanion with significant Pd-Tl (286 - 287 pm) and Tl-Tl (323 - 329 pm) interactions. The europium atoms fill distorted hexagonal channels of the [PdTl2] polyanion. Susceptibility measurements show a magnetic moment of 7.46(5) μB/Eu atom, indicative of divalent europium. EuPdTl2 is a soft ferromagnet with a Curie temperature of TC = 12.5(5) K.
Preparation of Geminal Donor-Acceptor Units by Reactions of Low Valent Metal Halides with Iminium Chlorides
Authors: Tian Xin , Hagemann Michael , Fröhlich Roland , Pape Tania , Mitzel Norbert W. 
Published: February 2015

Abstract
The organogallium compound [{Me2NCH2Ga(Cl,I)2}2] (1) and the organoindium compounds [Me2NCH2In(Cl,Br)2]2 (2) and [Me2NCH2InCl2]2 (3) have been prepared by the reactions of the low valent metal halides “GaI”, InBr and InCl with the iminium salt [Me2N=CH2]Cl. Compounds 1 and 2 are heterohalogen mixtures. These compounds were characterised by NMR spectroscopy and mass spectrometry, 1 furthermore by single crystal X-ray diffraction and 3 by elemental analysis. During the work-up procedure, minor amounts of hydrogen halide adducts of compounds 2 and 3 were isolated as single crystals, which contain a further equivalent of THF. These zwitter-ionic species Me2N(H)CH2In(Br,Cl)3·THF (2·H(Cl,Br)·THF) and Me2N(H)CH2InCl3 ·THF (3 ·HCl ·THF) were identified by single crystal X-ray diffraction. Methylation reactions of compounds 1 and 2 with MeLi gave two well-established compounds [{Me2NCH2GaMe2}2] and [{Me2NCH2InMe2}2], which were obtained previously by different preparation procedures.
A New Type of Non-Kekulé Diradicals with Triplet Ground States. I. Polymethine Systems
Authors: Tyutyulkov Nikolai , Drebov Nedko , Müllen Klaus , Dietz Fritz 
Published: February 2015

Abstract
It is shown theoretically that the ground state of a new class of non-Kekulé polymethine molecules can be a triplet state with non-degenerate singly occupied MOs. The investigated polymethine cyanine cations, polymethine oxonol anions, and neutral polymethine merocyanines are derivatives of the stable 2-azaphenalenyl radical whose pentamethine fragment is part of the polymethine chain.
Zinc-Mediated Synthesis of Diaryl Selenides from Diaryl Diselenides and Diaryliodonium Salts in Aqueous Media
Authors: Movassagh Barahman , Fazelia Azadeh 
Published: February 2015

Abstract
An efficient synthetic method has been developed for the preparation of symmetrical and unsymmetrical diaryl selenides through a one-pot reaction of diaryl diselenides and diaryliodonium salts in the presence of Zn/AlCl3 system in aqueous media.
Solid State Synthesis of CaMnO3 from CaCO3-MnCO3 Mixtures by Mechanical Energy
Authors: Berbenni Vittorio , Milanese Chiara , Bruni Giovanna , Cofrancesco Pacifico , Marini Amedeo 
Published: February 2015

Abstract
A solid state synthesis of calcium manganite (CaMnO3) is described where equimolecular mixtures CaCO3:MnCO3 have been subjected to mechanical stress (high energy milling) so yielding CaCO3-MnCO3 solid solutions of nanometric particle size. TG measurements have shown that a link exists between milling time, the extent of non-stoichiometry and the milling-induced decomposition of MnCO3 to Mn3O4. A short (2 h) annealing at 850 °C performed on a sample mixture milled for 25 h leads to non-stoichiometric CaMnO3−x. No sure conclusion could be drawn for the stoichiometry of CaMnO3 obtained, under the same annealing conditions, from a mixture milled for longer time (150 h). No synthesis of CaMnO3 could be effected by long (48 h) annealing at 1200 °C of mixtures that had not been subjected to mechanical stress.
Synthesis, Spectral and Thermal Properties, and Crystal Structure of Bis(ethylenediamine)(aqua)copper(II) (Bis)syringate Ethylenediamine Dihydrate [Cu(en)2(H2O)](sy)2(en)(H2O)2
Authors: Heren Zerrin , Pa§aoğlu Hümeyra , Ka§tas Gökhan , Vurucu Leyla , Büyükgüngör Orhan 
Published: February 2015

Abstract
The complex [Cu(en)2(H2O)](sy)2(en)(H2O)2 has been synthesized and characterized by its electronic and vibrational spectra. The molecular structure of the complex has been determined by X-ray diffraction methods. The complex crystallizes in the orthorhombic space group Pnma with unit-cell parameters a =10.7236(5), b= 20.4660(10), c= 14.4523(11) Å and Z=4. In the cation, the Cu(II) ion has a distorted square pyramidal coordination with two bidendate (en) ligands forming the basal plane and a H2O molecule in the apical position. The complex cations and syringate anions constitute chains along the b axis in -A-B-A- fashion. The members of the chains are linked by through N-H ···O hydrogen bonds. The (en) molecules are responsible for connecting adjacent layers.
High Pressure and Chemical Bonding in Materials Chemistry
Authors: Demazeau Gérard 
Published: February 2015

Materials chemistry under high pressures is an important research area opening new routes for stabilizing novel materials or original structures with different compositions (oxides, oxoborates, nitrides, nitridophosphates, sulfides,. . .).
Due to the varieties of chemical compositions and structures involved, high pressure technology is also an important tool for improving the investigations on chemical bonding and consequently the induced physico-chemical properties.
Two different approaches can be described: (i) the chemical bond is pre-existing and in such a case, high pressures lead to structural transformations, (ii) the chemical bond does not exist and high pressures are able to help the synthesis of novel materials. In both cases the condensation effect (ΔV < 0 between precursors and the final product) is the general rule. In addition, through the improvement of the reactivity, high pressures can lead to materials that are not reachable through other chemical routes.
Rb2P2S6 – A New Alkali Thiophosphate: Crystal Structure and Vibrational Spectra of Rubidium Hexathiodiphosphate(V)
Authors: Gjikaj Mimoza , Ehrhardt Claus , Brockner Wolfgang 
Published: February 2015

Abstract
Single crystals of rubidium hexathiodiphosphate(V), Rb2P2S6, have been obtained and investigated by single crystal X-ray diffraction, and IR/FIR and Raman spectroscopy. The title compound crystallizes isotypically to the potassium, caesium and thallium analogues in the orthorhombic space group Immm (no. 71) with a = 8.485(3), b= 6.953(3), c =9.259(3 Å , and Z = 2, final R1= 0.0579 and wR2 = 0.0987. The crystal structure is characterized by discrete [P2S6]2− anions (edge-sharing double-tetrahedra) with D2h symmetry. Rubidium is coordinated by ten sulfur atoms forming a slightly distorted two-capped tetragonal prism with a coordination number CNRb 10. The FT-Raman and FT-IR/FIR spectra have been recorded and a factor group analysis was carried out.
Synthesis, Spectroscopic and X-Ray Structure Characterisation of Bis(tetramethylammonium), Bis(tetraethylammonium) and Bis(tetrapropylammonium) Tetrathiotungstates
Authors: Poisot Martha , Näther Christian , Bensch Wolfgang 
Published: February 2015

Abstract
The three new tetraalkylammonium tetrathiotungstates ((Me)4N)2[WS4] (1), ((Et)4N)2[WS4] (2) and ((nPr)4N)2[WS4] (3) were prepared via a direct salt substitution using (NH4)2[WS4] as starting material. Compound 1 crystallises in the chiral orthorhombic space group P212121 with a = 8.9433(4), b = 15.5658(9) and c = 37.279(2) Å . Compound 2 crystallises in space group P21/n with lattice parameters a = 16.6695(12), b = 9.3415(6), c = 16.9965(13) Å and β = 117.185(15)°. The third compound 3 crystallises in space group C2/c with the lattice parameters a = 32.440(2), b = 13.8453(6), c = 15.0563(10) Å and β = 109.19(7)°. The structures of all compounds consist of slightly distorted [WS4]2− tetrahedra and tetraalkylammonium cations which are packed in different ways. One interesting observation is that the disorder of parts of the alkyl groups decreases with increasing chain length. The IR and Raman spectra show the vibrations of the [WS4]2− tetrahedron with a slight shift with increasing alkyl chain length. The most prominent IR-band of the [WS4]2− tetrahedra is broad but not split, indicating that the distortion of the tetrahedra is small.
Metal Tetrahydroborates and Tetrahydroborato Metallates, 30 [1]. Alkoxo-Substituted Alkali Metal Tetrahydroborates: Studies in Solution and Structures in the Solid State
Authors: Knizek Jörg , Nöth Heinrich , Warchhold Markus 
Published: February 2015

Abstract
Reactions of MBH4 (M = Li, Na, K) with tBuOH, Ph3COH, PhOH, F5C6OH, and 2,4- tBu2C6H3OH in THF in a 1 : 1 ratio were followed by 11B NMR spectroscopy. No M[H2B(OR)2] species could be detected, but minor amounts of M[H3BOR] and larger amounts of M[HB(OR)3]. In the reaction of LiBH4 with 2,4-tBu2C6H3OH also a fair proportion of (RO)2BH was generated. The perfluorophenolato borane (F5C6O)2BH·THF was prepared from the phenol and BH3 ·THF in THF solution. It is unstable to disproportionation. Compound (C6F5O)3B·THF was isolated and its crystal structure determined. Reaction of LiBH4 with F5C6OH in hexane generated a solid that proved to be Li[H2B(OC6F5)2]. It is unstable in THF. On the other hand, 2,2’-dihydroxydiphenyl in the presence of secondary amines reacts to give Li[C12H8O2B(NR2)2] (3 - 5). Li[B(O2C12H8)2], 2, is formed when HN(tBu)Ph is used as a secondary amine. The unstable phthalatoborane H{C6H4[C(O)O]2}BH·THF (7), is stabilized as its pyridine adduct (phth)BH·py (8). 7 reacts with 3 equivalents of LitBu to give [Li(HBtBu)3] (11), isolated as its tris(THF) solvate. Analogously, 7 reacts with LiNMePh to produce compound Li[HB(NMePh)3] (10). Similarly, 7 and NaOtBu (molar ratio 1 : 3) give access to Na[HB(OtBu)3] (9). In attempts to grow single crystals, specimens resulting from a hexane solution showed that partial hydrolysis has occurred to give Na[HB(OtBu)3]·Na[(tBuO)2BO]·Na[tBuOB(O)H], which crystallizes as a centrosymmetric dimer. While catecholborane when treated with LitBu in THF and DME gave access to (dme)2Li[catB- (tBu)2], 12 (dme)2, several compounds were observed when Li piperidide was used as nucleophile. Amongst these, the most interesting one was (dme)(THF)Li2(cat)(catBH), 13 (dme)THF, the crystal structure of which was determined. In all cases where the borate species carried OR groups the O atoms of the RO or PhO group coordinate with the alkali metal cation. DFT calculations for the series of anions H4−nBXn
− showed that HBX3
− is the most stable species for X = F, OH, NH2. This confirms experimental results.
A New Acyclic Diterpene Glycoside from Nicotiana attenuata with a Mild Deterrent Effect on Feeding Manduca sexta Larvae
Authors: Jassbi Amir Reza , Zamanizadehnajari Simin , Kessler Danny , Baldwin Ian T. 
Published: February 2015

Abstract
To investigate the role of secondary metabolites in the feeding behavior of Manduca sexta larvae feeding on Nicotiana attenuata, an aqueous acetone extract of the aerial parts of the plant was subjected to feeding-performance bioassay-guided fractionation. We isolated three 20- hydroxygeranyllinalool glycosides from the leaves of N. attenuata, which acted as mild deterrents to the feeding herbivore M. sexta. One of the diterpenoid glycosides, attenoside (3), is a novel natural product. The structures of the compounds were determined using APCI mass spectrometry and 1- and 2D-NMR spectroscopy.
New Withanolides from Fresh Berries of Withania somnifera
Authors: Lal Payare , Misra Laxminarain , Sangwan Rajender S. , Tuli Rakesh 
Published: February 2015

Abstract
The chloroform extract of the fresh berries of Withania somnifera has been investigated to afford stigmasterol, its glucoside, withanone, 27-hydroxy withanolide A along with two new withanolides, namely, iso-withanone (1) and 6α,7α-epoxy-1α,3β ,5α-trihydroxy-witha-24-enolide (2). Compound 1 possesses an uncommon 17α-oriented side chain whereas compound 2 has 1α,3β - dihydroxy group which is a molecule of biogenetic significance for withasteroids.
Triterpenoid Saponins from Astragalus corniculatus
Authors: Krasteva Ilina , Nikolov Stefan , Kaloga Maki , Mayer Gisela 
Published: February 2015

Abstract
Two new triterpenoid saponins were isolated from the ethanolic extract of the aerial parts of Astragalus corniculatus Bieb. The structures of the saponins were elucidated as 3β -O-[O-4-oxopentopyranosyl-( 1 → 2)-β -D-glucopyranosyl]-21α-hydroxyolean-12-ene-28-oic acid (1) and 21α- hydroxyolean-12-ene-28-oic acid 3β -4-oxo-pentopyranoside (2) by chemical and spectral methods.
A New Pigment from the Fruiting Bodies of the Basidiomycete Lactarius deliciosus
Authors: Yang Xiao-Long , Luo Du-Qiang , Liu Ji-Kai 
Published: February 2015

Abstract
A new purple azulene pigment (1) was isolated from the fruiting bodies of the basidiomycete Lactarius deliciosus together with one known pigment (2). The structures of the pigments were established on the basis of spectral evidence (MS, IR, 1D- and 2D-NMR experiments).
Synthesis and Characterization of New Diiron and Diruthenium μ-Aminocarbyne Complexes Containing Terminal S-, P- and C-Ligands
Authors: Albano Vincenzo G. , Busetto Luigi , Marchetti Fabio , Monari Magda , Zacchini Stefano , Zanotti Valerio 
Published: February 2015

The diiron aminocarbyne complexes [Fe2{μ-CN(Me)(R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (R = Xy1, 1a; R = Me, 1b; R = CH2Ph, 1c; Xy1 = 2,6-Me2C6H3) undergo replacement of the coordinated nitrile by halides, diethyldithiocarbamate, and dicyanomethanide to give [Fe2{μ-CN(Me) (R)}(μ-CO)(CO)(X)(Cp)2] complexes (R = Me, X = Br, 4a; R = Me, X = I, 4b; R = CH2Ph, X = Cl, 4c; R = CH2Ph, X = Br, 4d; R = CH2Ph, X = I, 4e; R = Xy1, X = SC(S)NEt2, 5a; R = Me, X = SC(S)NEt2, 5b; R = Xy1, X = CH(CN)2, 7), in good yields. The molecular structure of 5a shows an unusual η1 coordination mode of the dithiocarbamate ligand. Similarly, treatment of [M2{μ-CN(Me) (R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (M = Fe, R = Xy1, 1a; M = Fe, R = Me, 1b; M = Ru, R = Xy1, 2a; M = Ru, R = Me, 2b) with a series of phosphanes generates the cationic complexes [M2{μ- CN(Me)(R)}(μ-CO)(CO)(P)(Cp)2][SO3CF3] (M = Fe, R = Xy1, P = PPh2H, 6a; M = Fe, R = Xy1, P = PPh3, 6b; M = Fe, R = Xy1, P = PMe3, 6c; M = Fe, R = Me, P = PMe2Ph, 6d; M = Fe, R = Me, P = PPh3, 6e; M = Fe, R = Me, P = PMePh2, 6f; M = Ru, R = Xy1, P = PPh2H, 6g; M = Ru, R = Me, P = PPh2H, 6h), in high yields. The molecular structure of 6a has been elucidated by an X-ray diffraction study. The reactions of [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(NCR′)(Cp)2][SO3CF3] [R′ = Me, 1a; R′ = tBu, 3] with PhLi and PPh2Li yield [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(Ph)(Cp)2] (8) and [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(PPh2)(Cp)2] (9), respectively. The molecular structure of 8 has been ascertained by X-ray diffraction. Conversely, the reaction of 1a with MeLi generates the aminoalkylidene compound [Fe2{C(Me)N(Me)(Xy1)}(μ-CO)2(CO)(Cp)2] (10).
Finally, the acetone complex [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(OCMe2)(Cp)2][SO3CF3] (12) reacts with lithium acetylides to give complexes [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(C≡CR)(Cp)2] (R = p-C6H4Me, 11a; R = Ph, 11b; R = SiMe3, 11c), in high yields. Filtration through alumina of a solution of 11a in CH2Cl2 results in hydration of the acetylide group and C-Si bond cleavage, affording [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO){C(O)Me}(Cp)2] (12).
Synthesis and Single Crystal X-Ray Structure of Ethyl 2-(1,3-Benzoxazol- 2-yl)-5-oxo-3-(4-toluidino)-2,5-dihydro-4-isoxazolecarboxylate
Authors: Souldozi Ali , Khalafy Jabbar , Marjani Ahmad Poursattar , Ślepokura Katarzyna , Lis Tadeusz , Ramazani Ali 
Published: February 2015

Abstract
Ethyl 5-oxo-3-(4-toluidino)-2,5-dihydro-4-isoxazolecarboxylate was prepared from the reaction of diethyl 2-(4-toluidinocarbothioyl)malonate with hydroxylamine. Its reaction with 2- chlorobenzoxazole gave the corresponding N-substituted isoxazolone. The structure of the final product 4 was confirmed by IR, 1H and 13C NMR spectroscopy and mass spectrometry, and by X-ray single crystal structure determination.
Secondary Interactions in Bromomethyl-substituted Benzenes: Crystal Structures of Three α,α′-Bis-bromoxylenes, 1,2,3,5-Tetrakis(bromomethyl)benzene, and 1,2,4,5-Tetrakis(bromomethyl)benzene
Authors: Jones Peter G. , Kuś Piotr 
Published: February 2015

Abstract
X-Ray structure determinations of all three isomers of bis(bromomethyl)benzene and of two isomeric tetrakis(bromomethyl)benzenes show that the packing of the molecules is determined principally by interactions of the bromomethyl groups (C-H· · ·Br and Br· · ·Br), except for ortho-bis (bromomethyl)benzene, in which C-H· · ·π interactions play a major role.
Synthesis, Structure and Acid-Base Behaviour of Some 4-Hydroxycoumarin Derivatives
Authors: Stanchev Stancho , Maichle-Mössmer Cäcilia , Manolov Ilia 
Published: February 2015

Abstract
The compound 3,3′-[(4-hydroxy-3-methoxy-5-nitrophenyl)methylene]-bis(4-hydroxy-2H-1- benzopyran-2-one) (1) crystallizes in the monoclinic system, space group P21/n, with cell constants a = 16.859(4), b = 6.1624(15), c = 25.164(4) Å , β = 98.019(19)°. The two 4-hydroxycoumarin fragments are intramolecularly hydrogen-bonded between hydroxyl and carbonyl groups. The pH-dependent color changes of 4-hydroxycoumarin derivatives were studied by means of potentiometric and spectrophotometric titration. On the basis of the results obtained, the use of 3,3′-[(4-hydroxy-3- methoxy-5-nitrophenyl)methylene]-bis(4-hydroxy-2H-1-benzopyran-2-one) as an indicator in alkalimetry and acidimetry is proposed.
Xylodiol, a New Atisane Diterpenoid from Xylopia Langsdorffiana St.-Hil. & Tul. (Annonaceae)
Authors: Tavares Josean Fechine , Silva Marianna Vieira B. , Queiroga Karine F. , Diniz Margareth F. F. Melo , Filho José M. Barbosa , Haun Marcela , Melo Patrícia S. , Silvaa Marcelo Sobral da 
Published: February 2015

Abstract
Two diterpenes were isolated from the leaves of Xylopia langsdorffiana, the new ent-atisane- 7α,16α-diol named xylodiol (1) and the known 8 (17),12E,14-labdatrien-18-oic acid (2). The structures of these isolates were deduced by spectroscopic data interpretation. Compound 2was less toxic than xylodiol on V79 cells and hepatocytes.
“Covalent Magnetism” and Invar-like Behavior within Ternary Nitrides: An ab initio Study
Authors: Matar Samir F. , Houari Abdesalem , Belkhir Mohamed A. , Zakhour Mirvat 
Published: February 2015

Abstract
Magnetic properties and bonding analyses of perovskite structure-derived TFe3N (T = Ru, Os) nitrides have been investigated within density functional theory using both pseudo potential and all electron methods. At equilibrium, spin degenerate non-magnetic (NM) and ferromagnetic (FM) calculations of energy versus volume show that the ground state of the two compounds is ferromagnetic. Magnetic moments of Ru/Os and Fe, respectively, being situated at two different crystallographic sites are studied over a wide range of the cubic lattice parameter. The volume expansion indicates that iron atoms show itinerant magnetism while Ru and Os exhibit a localized behavior. Important magnetovolume effects are observed, with saturation of the magnetic moment reached in RuFe3N but not in OsFe3N. The electronic structure is visualized for the different binding characters Fe-N versus Ru/Os-N with the help of electron localization plots. The density of states of the ferromagnetic ground state is interpreted on the basis of a covalent magnetic model which goes beyond the Stoner rigid band model. An Invar-like behavior is predicted for the two nitrides.