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Research is presented concerning the development of a neoinstitutionalist framework which can be used to analyze the scientific careers of individuals over four distinct career stages ranging from apprentice to sponsor.

The ternary carbonate LiLa(CO3)2, previously obtained under supercritical CO2pressure conditions was prepared by a new and efficient way of synthesis. A 2:1 molar mixture of Li2(CO3) and LaCl3reacted in a silica tube at 400 °C. The crystal structure of LiLa(CO3)2was refined from X‐ray single‐crystal data and can be related with a caesium chloride type arrangement, where Li+and La3+ions occupy the cesium positions and (CO3)2–ions occupy all cubic voids. Cerium‐doped samples (LiLa(CO3)2:Ce) exhibit blue luminescence. The mineral bastnäsite was synthesized by the same preparative approach, departing from a 1:1 molar mixture of LaF3and Li2(CO3) being reacted at 450 °C.

Rare earth carbodiimide silicates RE2(CN2)(SiO4) with RE= Y, La, and Pr were synthesised by solid state metathesis reactions of RECl3, Li2(CN2), and SiO2or Li2SiO4, respectively, in silica tubes at 550 °C. All three compounds crystallise with different structures, although all of them represent distorted derivatives of the sodium chloride type structure. The structure of Y2(CN2)(SiO4) was refined monoclinically (C2/m, Z= 2, a= 1301.382(5) pm, b= 377.630(1) pm, c= 527.656(2) pm, β= 93.9816(2) °) from X‐ray powder data. The crystal structure of La2(CN2)(SiO4) was refined in a different monoclinic space group (P21/c, Z= 4, a= 660.3(1) pm, b= 1282.0(2) pm, c= 656.2(1) pm, β= 105.23(2) °), and the structure of Pr2(CN2)(SiO4) was refined triclinically (P\bar{1}, Z= 2, a= 646.7(2) pm, b= 669.2(2) pm, c= 671.8(2) pm, α= 86.18(3) °, β= 73.22(3) °, γ= 74.08(3) °) from X‐ray single crystal data.

Solid state metathesis reactions have been established as a successful tool in syntheses of rare earth carbodiimide compounds. Current results evidence the new compounds LiRE(CN2)2with RE= La, Ce and the carbodiimide nitride Ce3(CN2)3N. LiRE(CN2)2compounds were synthesized by solid state metathesis reactions between REF3and Li2(CN2) in 1:2 molar ratio. Ce3(CN2)3N was obtained by thermal conversion of LiCe(CN2)2., Crystal structures of LiLa(CN2)2and Ce3(CN2)3N were determined from X‐ray single crystal data (LiLa(CN2)2: P21/m, a= 542.4(2) pm, b= 379.16(7) pm, c= 1013.0(3) pm, β= 101.35(3) °; Ce3(CN2)3N: P212121, a= 672.97(9) pm, b= 1309.8(2) pm, c= 1697.7(3) pm) and LiCe(CN2)2was assigned from indexed X‐ray powder diffraction data (LiCe(CN2)2: a= 541.9(1) pm, b= 374.50(8) pm, c= 1008.8(2) pm, β= 101.21(1) °)., The crystal structure of LiLa(CN2)2represents a layer‐like arrangement of ions as typical for this type of compounds. The crystal structure of Ce3(CN2)3N reveals chains of [NCe4] tetrahedra running parallel to each other, and trigonal prismatic to trigonal antiprismatic arrangements of six distinctly interconnected [Ce3–NCN–Ce3] units. Both structures contain (CN2)2–ions deviating from their ideal D∞hsymmetry, with C–N distances ranging between 121 and 126 pm and N–C–N angles near 180°.

The new carbodiimide compounds LaF(CN2) and LiPr2F3(CN2)2were obtained as crystalline powders by solid‐state metathesis reactions from 1:1 molar ratios of REF3(RE= rare earth) and Li2(CN2) at temperatures between 500 and 700 °C over 4 days in fused copper ampoules. Higher proportions of Li2(CN2) in reactions yielded RE2(CN2)3compounds, including the new Eu2(CN2)3. Single‐crystal structure refinements were performed for LaF(CN2) and LiPr2F3(CN2)2. Homologous LiRE2F3(CN2)2compounds with RE= Ce, Pr, Nd, Sm, Eu, Gd were assigned by isotypic indexing of their XRD patterns. The crystal structure of LaF(CN2) contains planar [La3F3] layers being interconnected by carbodiimide ions, and is related with that of the mineral bastnäsite (REF(CO3)).

Solid state metathesis reactions between cyanuric chloride and C–N–H or alkali metal–(B–)C–N compounds, respectively, were carried out in the temperature range between 150 °C to 500 °C, studying intermediate stages of reactions and targeting the formation of carbon nitride materials by elimination of HCl or alkali metal chlorides. Although cyanuric chloride was reacted with quite a number of different reaction partners such as melamine, cyanamide, lithium nitride, lithium or sodium carbodiimide, lithium nitridoborate or sodium dicyandiamide, always the same intermediate compounds appeared in the reactions mixtures. Colorless, needle‐shaped crystals of the tertiary amine N(C3N3Cl2)3(1) were obtained at temperatures around 200–250 °C. Temperatures as high as 400 °C yielded yellow, plate‐like crystals of the heptazine compound C6N7Cl3(2). At even higher temperatures, the reaction products were of poorer crystallinity, but evidence of the formation of another crystalline intermediate was given by X‐ray powder diffraction and electron diffraction experiments. This third intermediate is assumed to be a tertiary amine, quite similar to 1, however, having heptazine ligands instead of triazine ligands and is assigned with the formula N(C6N7Cl2)3(3). Theoretical calculations were performed for the structures and the vibrational spectra of 1and 3. Theoretical calculations and a structure refinement based of X‐ray powder diffraction data yielded a plausible structural model for compound 3.

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Adjustable networks: The tetracyanamidosilicates A(RE)[Si(CN2)4] are formed by solid‐state metathesis reactions and contain the novel [Si(CN2)4]4−ion. Depending on the alkali metal ion (A=K or Rb), orthorhombic or tetragonal network structures are formed in which the rare‐earth (RE) ions have differently distorted trigonal‐dodecahedral environments. The crystal structure of RbLa[Si(CN2)4] is shown (Rb yellow, La red, Si gray, C brown, N blue).

The new compound Ce3Ni2(BN)2N was synthesized by a modified solid state metathesis reaction. The crystal structure of Ce3Ni2(BN)2N was found to be isotypic with the superconducting compound La3Ni2(BN)2N, according to Rietveld refinements performed on X‐ray powder data (I4/mmm, Z= 2, a= 3.5817(1) Å, c= 20.283(1) Å).

Synthesis of Y2O2(CN2) and Luminescence Properties of Y2O2(CN2):Eu

Europium aluminium garnet (Eu3Al5O12, EAG) was synthesized by an aqueous sol‐gel process and subsequent thermal annealing at 800 – 850 °C. Eu3Al5O12crystallizes cubic (${\rm (} Ia \bar{\mathit 3} d, {\rm a = 12.140(1)\AA)}$and its crystal structure was refined from X‐ray powder data. The refined oxygen position in the structure of EAG yields four shorter and four longer distances between europium and the eight surrounding oxygen atoms, forming a distorted dodecahedron. Pure Eu3Al5O12can be treated at temperatures around 1000 °C before it converts into perovskite‐like EAP near 1300 °C.

Synthesis and Structure of the Basic Alkaline Earth Nitrates Sr2(OH)3NO3and Ba2(OH)3NO3

The sublimation of 2-amino-4,6-dichloro-1,3,5-triazine yielded well developed needle-shaped crystals whose X-ray-powder pattern did not match with that of the known orthorhombic compound with the space group P212121[1]. The investigation of a needle-shaped single crystal revealed a new monoclinic modification, which crystallizes in the space group P21/c. At T= 220 K the following lattice parameters were refined: a= 8.403(1) Å, b= 12.152(1) Å, c= 13.898(2) Å and β= 123.01(1)°. The unit cell volume amounts to 1190(1) Å3for 8 formula units.

Solid state metathesis reactions between LaCl3and Li2(CN2) carried out in silica ampoules at 600 °C over two days resulted in the formation of a light gray powder, later identified to be lanthanum chloride cyanamide. Single crystals were obtained as colourless transparent plates using a LiCl‐KCl flux. The crystal structure of LaCl(CN2) was solved and refined from X‐ray single crystal data (P21/m (no. 11), Z = 2, a= 5.330(1) Å, b= 4.0305(8) Å, c= 7.545(1) Å, V= 159.24(5) Å3, β= 100.75(2)°). The structure of LaCl(CN2) is closely related to the tetragonal LaOCl (PbFCl type) structure and contains a [La2Cl2]4+block layer and two layers of (CN2)2‐ions in an alternating sequence. The La3+ion in LaCl(CN2) is situated in a polyhedron composed of four chloride ions on one side and five cyanamide ions on the other side. Cerium and praseodymium analogues were identified from indexed powder patterns with analogous unit cells, assuming them to form isostructural compounds.

Schwarze oktaedrische Einkristalle von W6Cl18wurden bei der Reduktion von WCl4mit Graphit in einer Kieselglasampulle bei 600 °C erhalten. Die Einkristall‐Strukturanalyse ergab (Raumgruppe R 3¯, Z = 3, a = b = 1498, 9(1) pm, c = 845, 47(5) pm) die schon früher aus Pulverdaten ermittelte Kristallstruktur von W6Cl18.

Solid state metathesis reactions have been studied in fused silica tubes, by differential thermal analysis, and by X‐ray powder diffraction. A selection of reactions between metal (La, Nb, and Ni) chlorides and lithium nitride or lithium acetylide were investigated to get more insight into reaction pathways and intermediate reaction stages that may be adopted on course of the formation of metal nitrides or carbides. Intermediate compounds are considered to be important because they can control the reactivity of a system. Such compounds were traced by changing the molar ratios of reaction partners away from the salt‐balanced binary metal nitride or carbide target compositions.

Cr3C2was obtained from arc-melting of pellets made of carbon and chromium. The structure of Cr3C2was determined by single crystal X-ray diffraction (Pnma, Z = 4, a = 553.99(6), b = 283.27(4), c = 1149.4(1) pm, R1 = 0.019 and wR2 = 0.037 for all collected reflections). The crystal structure contains isolated carbon atoms which reside inside of trigonal prismatic voids of metal atoms. The compound exhibits temperature independent paramagnetism. The electronic structure of Cr3C2has been investigated using extended Hückel calculations.

Ca3BN3wurde als hellgraues Pulver aus Reaktionen äquimolarer Mengen von Ca3N2und BN bei 1000 °C hergestellt. Die Kristallstruktur wurde aus einem Pulver‐Röntgendiagramm nach der Rietveld‐Methode verfeinert. Ca3BN3kristallisiert tetragonal in der Raumgruppe P4/mmm mit den Gitterparameter a = b = 354, 94(1) pm und c = 821, 36(3) pm. Die Kristallstruktur enthält linear gebaute (BN2)3—‐Ionen mit B—N‐Bindungslängen von 135, 2(4) pm und ist topologisch mit der orthorhombischen (Pmmm) Hochdruck‐Modifikation von Mg3BN3identisch.

Im System Ca—Ni—Si wurden die neuen Verbindungen CaNi2Si und Ca3Ni3Si2hergestellt und ihre Strukturen röntgenographisch an Einkristallen bestimmt. CaNi2Si kristallisiert in der Raumgruppe P63/mmc (Nr. 194) mit den Gitterparametern a = 400, 38(5) pm, c = 988, 6(2) pm und Z = 2 (R1 = 0, 0307, wR2 = 0, 0553 für alle gemessenen symmetrieunabhängigen Reflexe) als Besetzungsvariante des ReB3‐Typs. Für Ca3Ni3Si2wurde eine orthorhombische Zelle mit der Raumgruppe Pnma (Nr. 62), Z = 4 und den Gitterparametern a = 926, 59(5) pm, b = 396, 69(2) pm, c = 1814, 1(2) pm gefunden (R1 = 0, 0435, wR2 = 0, 0605 für alle gemessenen symmetrieunabhängigen Reflexe). Ni und Si bilden gefaltete zweidimensional unendliche Schichten, die durch die Ca‐Atome separiert werden.

Das genaue Verständnis der elektronischen Vorgänge oder Mechanismen bei der Supraleitung bedeutet einen wichtigen Fortschritt für die Forschung. Bisher gibt es keine allgemeingültige Theorie der HTSL. Währenddessen werden supraleitende Materialien in der Technik erprobt und eingesetzt. Sie eröffnen einschneidende Veränderungen auf Gebieten der Energieübertragung, -speicherung, der Antriebstechnik und der Mikroelektronik. Gegenwärtig sind Oxocuprate aufgrund ihrer hohen Übergangstemperatur die bedeutendsten Materialien für Anwendungen auf dem Gebiet der Supraleitung. Aber auch die Erschlie—ung neuer Verbindungen mit anderen Elementen und Strukturen hilft, Geheimnisse des Mechanismus der Supraleitung zu lüften. Ob Supraleitung auch bei erheblich höheren Temperaturen als bisher möglich ist, werden wir erst in der Zukunft erfahren. Die Entdeckung der Supraleitfähigkeit von MgB2 ist vielleicht ein wichtiger Schritt.Die Synthese neuer supraleitfähiger Materialien bleibt weiterhin der Intuition der Wissenschaftler überlassen, solange keine Theorie existiert, die Hilfestellungen für das nächste Experiment liefert. http://www.uni-tuebingen.de/AK_H.-J.-Meyer/

Eine von insgesamt vier Modifikationen von CaC2ist das sogenannte metastabile Calciumcarbid, CaC2‐III, welches rein dargestellt wurde. Es bildet sich beim Erhitzen von monoklinem CaC2‐II (C2/c) ab etwa 150 °C und bleibt beim Abkühlen auf RT stabil. Die Struktur der Phase wurde mittels Röntgen‐Pulverdaten verfeinert (C2/m, Z = 4, a = 722,6(1) pm, b = 385,26(7) pm, c = 737,6(1) pm, β = 107,345(2)°). Beim Zerreiben der Phase wird eine Rückumwandlung in CaC2‐II induziert, und beim Erhitzen erfolgt bei 460 °C ein reversibler Phasenübergang in die kubische Modifikation (CaC2‐IV). Mittels 13C‐MAS‐NMR‐Messungen werden Unterschiede zwischen den drei bei Raumtemperatur stabilen Strukturen CaC2I–III aufgezeigt, insbesondere die Präsenz von zwei unterschiedlichen Kohlenstoffatomen in der Struktur der Titelverbindung.

Die Verbindung W6Cl18wurde nach zwei Methoden dargestellt; durch Oxidation von W6Cl12mit CCl4im Autoklav und durch Reaktion von W6Cl12mit Cl2im Strömungsrohr. Beim Erhitzen unter Normaldruck geht W6Cl18bei 400 °C in W6Cl12über. Die Kristallstruktur von W6Cl18wurde aus Röntgen‐Pulverdaten nach der Rietveld‐Methode verfeinert. Die ungewöhnlichen elektronischen Verhältnisse des 18‐Elektronen‐Clusters [W6Cl12]Cl6werden mit denen des elektronenpräzisen 24‐Elektronen‐Clusters [W6Cl8]Cl4verglichen. Die Verbindung ist paramagnetisch mit zwei Elektronen in antibindenden Energiezuständen.

Wasserfreies CaCl2entsteht bei der Reaktion von CaCO3mit NH4Cl. Die Reaktion verläuft über ein Zwischenprodukt, das als NH4CaCl3charakterisiert wird. Es kristallisiert im GdFeO3‐Typ und zersetzt sich bei höheren Temperaturen zu CaCl2und NH4Cl. Bildung und Zerfall des Zwischenproduktes sowie die Entstehung von CaCl2wurden röntgenographisch und thermoanalytisch verfolgt.

Für die Erdalkalimetallacetylide CaC2, SrC2und BaC2kann die Existenz von jeweils drei polymorphen Strukturen angenommen werden, die monokline Tieftemperaturform, die tetragonale Form und die kubische Hochtemperaturform. Einkristallstrukturanalysen und 13C‐MAS‐NMR‐Messungen ergaben, daß die C22–‐Ionen in den tetragonalen Strukturen axialsymmetrisch angeordnet sind. Allerdings enthielten die von uns synthetisierten CaC2‐Proben stets Anteile von monokliner und tetragonaler Phase. Raman‐Spektren von CaC2‐Proben zeigten die Präsenz zweier verschiedener C2‐Streckschwingungsbanden. Die aus der Koexistenz dieser beiden Phasen resultierende Problematik bei der Interpretation von 13C‐MAS‐NMR‐Spektren wird diskutiert.

The New Ternary Boride Mg8Pt4B and the New Intermetallic Compound PtMg2

Nb3Cl8wurde durch Reaktion von NbCl5mit Niob‐Metallpulver in einer geschlossenen Quarzglasampulle bei 700 °C dargestellt. Aus einer LiCl‐Schmelze isolierte Einkristalle wurden für die Strukturbestimmung mit einem IPDS‐Röntgendiffraktometer (Raumgruppe P 3 m1, Z = 2, Gitterkonstanten a = b = 672,95(7) pm, c = 1223,2(2) pm (bei 100 K), R1 = 0,029, wR2 = 0,064 für alle unabhängigen Reflexe) und die Messung des elektrischen Widerstandes ausgewählt. Die Lithium‐Einlagerung in die Struktur von Nb3Cl8wurde elektrochemisch untersucht.

The title compound is prepared by solid state reaction of EuF3, EuF2+x, and Li2(CN2) at 700 °C and characterized by single crystal XRD, 151Eu Moessbauer spectroscopy, and magnetic measurements.

A new route to the ternary carbonate (III), previously obtained under supercritical CO2pressure conditions, is described.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.