Zur Kenntnis von Sr2CuO2Br

Inhaltsübersicht. Sr₂CuO₂Br wurde in geschlossenen Cu-Bömbchen dargestellt und an Einkristallen röntgenographisch untersucht (a = 4,0235; c = 28,5103 A; Raumgruppe D⁵_2d–R$3m). Sr²⁺ besitzt oktaedrische Koordinationspolyeder aus je drei Br^– und O^2–. Die Oktaeder sind in Doppelschichten angeordnet und werden von hantelförmig koordinierten Cu⁺-Ionen längs [001] verknüpft. About Sr₂CuO₂Br Single crystal of the unknown compound Sr₂CuO₂Br were prepared in closed Cu-tubes and examined by single X-ray diffractometer investigation (a = 4.0235; c = 28.5109 A; space group D⁵_3d–R$3m). Sr²⁺ has octahedral coordination of 3 Br^– and 3 O^2–. Cu⁺ shows a dumb-bell-like O^2– surrounding.     

Zur Kenntnis von Sr2CrMnO6

About the New Compound Sr₂CrMnO₆ Sr₂CrMnO₆ was prepared and investigated by X-ray single crystal data (a = 541.6; c = 664.0 pm; space group C–P3 ). The structure is related to the distorted perovskites, the differences to SrCrO₃ and SrMnO₃ are discussed.     

(Sr2N)H: Untersuchungen zur Redox‐Intercalation von Wasserstoff in Sr2N

(Sr₂N)H: On the Redox-Intercalation of Hydrogen into Sr₂N Strontium-nitride-hydride is obtained as brown-yellow single phase powder by reaction of strontium-subnitride (Sr₂N) with hydrogen (200 bar, 620 K) and subsequent treatment under vacuum (10⁻⁶ bar, 870 K). The structure determination was carried out by a combination of X-ray and neutron diffraction experiments on a deuterated sample. The elemental composition of the ternary compound was confirmed by means of chemical analyses. (Sr₂N)D crystallizes in the space group with a = 381.91(2) pm and c = 1887.61(2) pm. Strontium (Sr²⁺) in the crystal structure of (Sr₂N)D is arranged with an only slightly distorted ccp-motif. Nitrogen (N³⁻) and deuterium (D⁻) occupy the octahedral voids of the Sr²⁺-matrix in an ordered manner resulting in an alternating sequence of layers (anti-α-NaFeO₂-type structure).     

Synthese und Kristallstruktur von Sr3Ga2O5Cl2 und Sr3Fe1.18Al0.82O5Cl2

Solid state reactions, by using a flux, lead to the new compounds Sr₃Ga₂O₅Cl₂ (A) and Sr₃Fe_1.18Al_0.82O₅Cl₂ (B). By means of single crystal X-Ray determinations a monoclinic symmetry (space group C ₂ ² -P2₁, (A):a=9.569 (2) Å; (B):a=9.550 (2) Å,Z=4) was found. Both compounds are not isotypic to Sr₃Fe₂O₅Cl₂ but crystallize like Ba₃Fe₂O₅Cl₂.

     

Herstellung und Eigenschaften der Verbindungen Sr2(MnO4)OH und Sr2(MnO4)OH·2H2O

Zusammenfassung Es wird die Herstellung der Verbindungen Sr₂(MnO₄)OH und Sr₂(MnO₄)OH·2H₂O beschrieben. Die Gitterkonstanten wurden aus den entsprechenden Pulverdiagrammen berechnet. Die Infrarotabsorptions-und die Reflexionsspektren im Sichtbaren sowie das magnetische und thermische Verhalten wurden untersucht und kurz besprochen.

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Preparation and properties of the compounds Sr₂(MnO₄)OH and Sr₂(MnO₄)OH·2H₂O

Methods for preparation of the anhydrous compound formulated as Sr₂(MnO₄)OH and of its dihydrate are described. Unit cell parameters, which are the same for both substances, have been calculated from X-ray powder diagramms. Infrared absorption and visible reflectance spectra as well as the magnetic and thermal properties are also reported and briefly discussed.

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Mit 4 Abbildung     

Relativistic electronic structure of the Sr2 molecule

Diatomic Sr2 has been proposed as a good candidate for precision measurement of possible time variation of fundamental constants. Precise knowledge of its vibrational structure and Stark shift of its levels in an optical lattice is required for realization of this proposal. Motivated by these ideas we have performed a numerical calculation of interatomic potentials and transition dipole moments of the Sr2 molecule using an ab initio relativistic configuration interaction valence bond self-consistent-field method.     

Polyaniline-functionalized porous adsorbent for Sr2+ adsorption

To support the nuclear safeguards particle analysis, a method was developed to produce micrometer-sized uranium oxide microspheres with a known uranium content and isotope ratio, which are intended to be characterized as certified reference material. To simplify handling of the produced particles, the collected particles have been transferred into ethanol suspensions. In addition to a demonstration of the suitability and new capabilities of such particle suspensions, such as the preparation of particle mixtures, the stability of the particles has been investigated and demonstrated with regard to dissolution and isotopic exchange.     

Sr2+-TiO2薄膜的制备及超亲水性

以钛酸丁酯作为前驱物,采用溶胶-凝胶法及浸渍-提拉法在载玻片上制备SrO-TiO2薄膜。通过X射线衍射和红外光谱等测试技术表征了SrO-TiO2粉末的结构,用紫外可见分光光度计测定薄膜的透光率,用接触角测试仪测定水与薄膜的接触角。结果表明,掺杂适量Sr2+后,SrO-TiO2粉末中TiO2晶粒的尺寸变小,SrO-TiO2薄膜表面吸附的羟基含量增多且稳定,可提高TiO2薄膜的超亲水性。经紫外光照１ｈ或自然光照５ｈ后,掺杂Sr2+（摩尔分数））为1.0％的SrO-TiO2薄膜与水的接触角接近于0°,表现出良好的亲水性。     

Ein Beitrag über Sr2RuO4 und Sr3Ru2O7 Zur Oktaederstreckung von M4+ in K2NiF4- und Sr3Ti2O7-Typ-Verbindungen

On the Thermal Decomposition of Hg₂I₂ and the Hg? I State Diagram Solid Hg₂I₂ decomposes congruently in Hg and HgI₂. The entropy S°(Hg₂I₂,s,298) = (55,5 ± 1) cal/K · mol and the enthalpy of formation ΔH_f°(Hg₂I₂, s, 298) = (?30,0 ± 2) kcal/mol are derived from the decomposition equilibrium. The phase diagram of the whole system Hg? I was constructed from investigations by DTA and total pressure measurements in the partial systems Hg? Hg₂I₂, Hg₂I₂? HgI₂, and HgI₂? I₂. It follows, that Hg₂I₂ melts incongruently at 297°C and decomposes in a Hg-rich and HgI₂-rich melt. The emerging miscibility gap is assumed to close at a temperature near 500°C.     

Transition from the layered Sr2RhO4 to the monodimensional Sr4RhO6 phase

Study of the structural changes occurring during the reduction process of the Sr2RhO4+delta, (214), n=1 term of the Ruddlesden and Popper series, shows that for delta <0.02 values, this material dissociates into the Sr4RhO6 (416) monodimensional phase, alpha = infinity, beta = 0 compound of the (A3B2O6)alpha-(A3B3O9)beta family, and Rh metal. During the first stage, this process occurs by the formation of an intergrowth between the (214) and (416) materials which can be only detected by high resolution electron microscopy and is easily interpreted on the basis of the structural relationship established between them. Further reduction allows the segregation of both phases as separated entities, which coexist with Rh metal. The dissociation process is reversible and, under oxidizing conditions, a layered material with anionic composition delta =0.06 is always obtained. This behaviour seems to be a general way of accommodating the compositional changes in layered A2BO4 phases where the B cation is always in a octahedral environment. The structural mechanism of this transformation is proposed, and the structural relationship between these two low-dimensional oxides is established.     

Diversity of Strontium Nitridogermanates(IV): Novel Sr4[GeN4], Sr8Ge2[GeN4], and Sr17Ge2[GeN3]2[GeN4]2

Single crystals of three new strontium nitridogermanates(IV) were grown in sealed niobium ampules from sodium flux. Dark red Sr₄[GeN₄] crystallizes in space group P2₁/c with a = 9.7923(2) Å, b = 6.3990(1) Å, c = 11.6924(3) Å and β = 115.966(1)°. Black Sr₈Ge₂[GeN₄] contains Ge^4– anions coexisting with [Ge^IVN₄]^8– tetrahedra and adopts space group Cc with a = 10.1117(4) Å, b = 17.1073(7) Å, c = 10.0473(4) Å and β = 115.966(1)°. Black Sr₁₇Ge₆N₁₄ features the same anions alongside trigonal planar [Ge^IVN₃]^5– units. It crystallizes in P1 with a = 7.5392(1) Å, b = 9.7502(2) Å, c = 11.6761(2) Å, α = 103.308(1)°, β = 94.651(1)° and γ = 110.248(1)°.     

Ca/Sr对(Sr2-xCax)MgSi2O7:Eu2+,Dy3+发光性能的影响

使用高温同相法制备了不同Ca/Sr对(Sr2-xCax)MgSi2O7:Eu2+,Dy3+长余辉材料发光材料,用X线粉末衍射表征该材料的相组成,用发射光谱、初始亮度和余辉时间对材料的发光性能进行表征,用热释光技术测定材料的陷阱深度.结果表明:Ca/Sr不仅能影响材料的发射光谱,而且还影响材料的初始亮度和余辉时间,随Ca/Sr(x值)增大,该类材料的发射光谱红移,余辉时间逐渐变短,而初始亮度值先变大后变小,陷阱深度逐渐变浅;当Ca/Sr为1时,材料的发光性能最好,这和材料具有合适深度的陷阱(0.5908 ev)有关.     

Zur Kenntnis der Struktur von Sr3(BN2)2

On the Structure of Sr₃(BN₂)₂ The structure of Sr₃(BN₂)₂ was determined on single-crystal X-ray data collected with a four-circle diffractometer. Sr₃(BN₂)₂ crystallizes in the cubic space group Im3 m (no. 229) with a = 764.56(3) pm and Z = 3. The structure contains linear BN^3?₂ ions with a B? N bond length of 135.8(6) pm. The straight forward synthesis employing metal nitrides plus boron nitride yielded crystalline powders of M₃(BN₂)₂ (M = Ca, Sr) at 1100°C (5 days). Cubic indexing of guinier patterns gave a = 765.8(1) pm for M = Sr and a = 734.7(2) pm for M = Ca. The structure refinement on a single crystal of Sr₃(BN₂)₂ revealed that one strontium site (2a; 0, 0, 0) is occupied by only about 50%. It has been tried to fully occupy this site with an alkali metal (A) to obtain ASr₄(BN₂)₃ (Z = 2). Reactions with A = Na yielded crystalline powders. Cubic indexing of the guinier pattern analogous to that of Sr₃(BN₂)₂ gave a = 754.2(1) pm.