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Zusammenfassung Im Dreistoff: Co-Al-Si werden zwei ternäre Phasen festgestellt, deren Zusammensetzung bei Co3Al3Si4 bzw. Co2AlSi2 liegt. Die erstgenannte kristallisiert im Ir3Ge7-Typ mit einer Gitterkonstante von:a w =8,075 kX·E., die zweite ist mit der Ni2Al3-Struktur isotyp und besitzt einen geringen homogenen Bereich. Die Gitterkonstanten sind:a=3,862–3,902;c=4,740 bis 4,781 kX·E.CrSi und MnSi bilden miteinander und mit den Monosiliciden von Eisen und Kobalt lückenlose Mischreihen (B 20-Typ). MnSi vermag 70 Mol% NiSi aufzunehmen, NiSi (B 31) nur etwa 5 Mol% MnSi. CrSi löst rd. 40 Mol% NiSi, dagegen ist CrSi in NiSi praktisch unlöslich.Mit 2 AbbildungenHerrn Prof. Dr.A. Zinke zu seinem 70. Geburtstag in Verehrung gewidmet.  相似文献   

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Silaethene Me2SiC(SiMe3)3 (1), unstable at −100°C with regard to dimerization, forms an adduct Me2SiC(SiMe3)2 · NMe3 (1 and NME, and can, therefore, serve as a source of 1. With 1 as an intermediate, the adduct 3 reacts with butadiene, cyclopentadiene, 2,3-dimethylbutadine, Ph2CNSiMe3, tBuN3, isobutene or acetone giving either cycloadducts or ene reaction products. Adduct 3 reacts with ROH (R = H, Me, tBu, Ph) to yield insertion products, probably by way of a proton adduct of 3, but not via 1. Other donors (D) of which NMe3 is an example form adducts 1 · D, producing a new class of silicon compounds. As the Lewis basicity of D, relative to 1, decreases (F ρ NMe3 ρ NEt3 ρ Br ρ THF), the resistance to decomposition of the adducts 1 · D to the dimer of 1 and D also decreases.  相似文献   

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Reaction of Cp2Ti(Me3SiC?CSiMe3) with O-Trimethylsilyl-benzaldoxime under Formation of a Nitrile and a Titana-Diazacyclopentene Complex Cp2Ti(Me3SiC?CSiMe3) ( 1 ) reacts with O-trimethylsilyl-benzaldoxime ( 4 ) to the titanocene-(η2-benzonitrile) complex 5 and 2,5-diaza-1-titana-3-cyclopentene 7 . The structure of 7 was obtained by X-ray crystal structure analysis ( 7 : orthorhombic, space group P212121, Z = 4, a = 7.955(2), b = 12.630(3), c = 19.426(4) Å).  相似文献   

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Zusammenfassung Die qualitative und quantitative Trennung von 2-Methyl- und 2-Äthyl-piperidin gelingt durch Gas-Chromatographie an Triäthanolamin auf Celite C 22 bei 90° C mit Wasserstoff als Trägergas.
Summary Separation and determination of 2-methyl- and 2-ethyl-piperidine can be achieved by gas chromatography on a column containing triethanolamine on Celite C 22 at 90° C. Hydrogen is used as the carrier gas.
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Complexes [CpRuSR]2 and [Cp RuSR]2, where Cp = η5-C5Me5, Cp = η5-C5Me4Et, R Et, tBu, (tBuO)3Si, are synthesized by exchange of the metboxo groups in [CpRuOMe]2 with the respective thiols. An X-ray molecular structure determination of [Cp RuSEt]2 confirms the dimeric structure with co-ordinatively unsaturated 16 VE Ru. The molecular geometry of the thiol-bridged dimer is compared to that of the oxo analogue.  相似文献   

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Trimerization of Dicyanamide Ions C2N3 in the Solid – Syntheses, Crystal Structures, and Properties of NaCs2(C2N3)3 und Na3C6N9 · 3 H2O The Tricyanomelaminate Na3C6N9 · 3 H2O is obtained by heating NaC2N3 to 500 °C and subsequent crystallization from water. According to the single-crystal structure determination (Na3C6N9 · 3 H2O: P62c; a = 1023.53(8), c = 650.85(15) pm, Z = 2, R1 = 0.0276, wR2 = 0.0710) in the solid cyclic C6N93– ions occur. Partial ion exchange and crystallization from water yields anhydrous NaCs2(C2N3)3. The X-ray structure determination (NaCs2(C2N3)3: P63/m, a = 700.01(4), c = 1449.29(7) pm, Z = 2, R1 = 0.0173, wR2 = 0.0432) reveals C2N3 ions in the solid. Calorimetric investigations and detailed IR spectroscopy of NaC2N3, Na3C6N9, Na3C6N9 · 3 H2O, as well as NaCs2(C2N3)3 reveal in combination with the structure analyses that NaC2N3 transforms to Na3C6N9 above 380 °C by trimerization of the C2N3 ions in the solid. Above 180 °C the hydrate Na3C6N9 · 3 H2O reversibly dehydrates.  相似文献   

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用具有大能隙的本征半导体(SrTiO3及SnO2)粉末作本体,分别掺杂1%(原子百分数)的Eu2O3;所得物质表现出Eu3+离子的线发射光谱特性,但相对发光强度及光谱形状有相当大的变化。X射线衍射结构分析显示Eu3+在SrTiO3晶格里是处在间隙位置,而它在SnO2晶格里则形成新物相Eu2Sn2O7。  相似文献   

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The effect of silyl substitution at the carbanionoid C atoms on structure and bonding of lithium-phosphinomethanides has been investigated by determination of the structure of {(Me2NCH2CH2NMe2)Li[(PMe2)CH(SiMe3)]}2, which has a six-membered ring (PCLi)2 in twist conformation, and so is markedly different in structure from both the bis-silyl substituted as well as the unsubstituted analogue.  相似文献   

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Treatment of K(P3C2tBu2) with Cu2I2 and PMe3 gave the binuclear complex [Cu(PMe3)2(μ-P3C2tBu2)2Cu(PMe3)2] via the isolated intermediate compound [Cu(PMe3)2(μ-P3C2tBu2)(μ-I)Cu(PMe3)2]. The reaction of K(P3C2tBu2) with [AuCl(PEt3)] on the otherhand gave the cation:anion complex [Au(PEt3)2][Au(η1-P3C2tBu2)2]. All complexes were fully characterised by multinuclear spectroscopy and single crystal X-ray diffraction studies.  相似文献   

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