Nitrido-silicate. II [1]. Hochtemperatur-Synthesen und Kristallstrukturen von Sr2Si5N8 und Ba2Si5N8 (original) (raw)
Related papers
Zeitschrift für Naturforschung B, 1993
Various six-membered cyclic sulfur diimides (3 a-f) were prepared by aminolysis o f the bis(chloro-dimethylsilyl)sulfur diimide (2) using N H 3 (a) and primary amines RNH-, [R = Me (b), Et (c), "Pr (d), "Bu (e), 'Pr (f)]. Except for R = H, non-cyclic intermediates, the Si-m onoam ino-(7) and Si,Si'-diamino derivatives o f 2 (8), were detetected for all groups R, including R = 'Bu (g). The reaction between R2SiCl2 and the sulfur diimide anion K [(N SN)SiM e3] gave non-cyclic silanes (9,10) and the eight-membered rings o f the type R2S i(N SN)2SiR 2 [R = Me (4), 'Bu (5)] o f which 5 was studied by X-ray analysis (m onoclinic, space group P 2,/c; planar ring system) and solid-state 15N and 29Si C P/M AS N M R spectrosco py. The ten-membered ring system 6 was obtained from the reaction between 1,2-dichlorotetramethyldisilane and bis(trimethylstannyl)sulfur diimide. All com pounds were studied by 'H, 13C, 15N and 29Si N M R. The <S15N N M R data proved useful to distinguish between fluxional systems with fast E /Z-Z /E isomerization (non-cyclic com pounds 8 and the ten-membered cycle 6). Hahn-Echo-extended (H EED) polarization transfer (INEPT) pulse sequences served to measure coupling constants ' / (29Sil5N amine) for the compounds 3 and 8. This also proved that the magnitude o f '7(29Sil5N NSN) must be small (< 1 Hz). In the case o f the com pounds 3, the rather small magnitude o f both '/ (29Si15N amine) and '/(^N 'H) (3a) indicated that the aminonitrogen atom adopts a pyramidal environment.
Synthese und Kristallstrukturen von PrSe2 und NdSe2
Zeitschrift f�r anorganische und allgemeine Chemie, 2005
Crystals of PrSe 2 and NdSe 2 can be made by chemical transport reactions starting from pre-annealed powders (800 Ϫ 600°C, 2 weeks, I 2 as transport agent). Both compounds adopt the CeSe 2-type structure. They crystallize in the monoclinic space group P2 1 /a with four formula units and lattice parameters of a ϭ 8.396(2) Å , b ϭ 4.184(1) Å , c ϭ 8.431(2) Å , and β ϭ 90.08(4)°(PrSe 2) and a ϭ 8.352(2) Å , b ϭ 4.164(1) Å , c ϭ 8.412(2) Å , and β ϭ 90.00(3)°(NdSe 2), respectively. The crystal structures consist
Eur J Inorg Chem, 1992
Silanol, acetyl-, crystal structure of 1 Microbial reduction Synthesis of the Si-Functional Acetylsilanes tBu(Me,SiCH,)[MeC(O)]SiF and tBu(Me,SiCH,)[MeC(O)]SiH as well as Synthesis and Crystal Structure of the Acetylsilanol tBu(Me,SiCH,)[MeC(O)]SiOH: Substrates for Microbial Reductions The racemic Si-functional acetylsilanes tBu(Me3SiCHz)-1-3 were found to be reduced by cells of Trigonopsis vari-[MeC(O)]SiF (1) and tBu(Me,SiCH,)[MeC(O)]SiH (2) and the abilis (DSM 70714) [ =SiC(O)Me + =SiCH(OH)Me]. The racemic acetylsilanol tBu(Me,SiCH,)[MeC(O)]SiOH (3) were crystal and molecular structure of 3 was studied by singlesynthesized from Si(OMe)4 (4) as substrates for microbial re-crystal X-ray diffraction. In the crystal, racemic 3 forms infinite ductions [4 + tBuSi(OMe)3 (5) + tBu(Me,SiCH,)Si(OMe), (6) chains built up by intermolecular 0-H-.O bonds between-+ tBu(Me3SiCHz)SiFz (?)-+ tBu(Me3SiCHz)(CHz= C(OMe)]SiF the hydroxyl and acetyl groups of molecules of the same ab-(8) + 1; 8 + tBu(Me3SiCH,)[CH2=C(OMe)]SiH (9)-+ 2; 6 + solute configuration. tBu(Me3SiCHz)[CHz = C(OMe)]SiOMe (10)-+ 31. Compounds 3 Si(1)-0(1) 1.638(1) Si(1)-C(5) 1.925(2) Si(1)-C(1) 1.846(2) C(1)-Si(1)-0(1) 11441) C(1)-Si(1)-C(5) 107.1(1) C(1)-Si(1)-C(7) 112.3(1) C(5)-Si(l)-0(1) 104.3(1) C(5)-Si(1)-C(7) 106.9(1) Si(1)-C(7) 1.9OO(2) C(5)-0(2) 1.227(2) C(5)-C(6) 1.493(3) C(7)-Si(1)-O(1) 111.4(1) Si(1)-C(1)-Si(2) 1 18.9(1) Si(1)-C(5)-C(6) 12 1.7(1) Si(1)-C(5)-O(2) 117.4(1) C(6)-C(5)-O(2) 1 20.8(2) Die erstmalig dargestellten Si-funktionellen Acetylsilane 1 und 2 sowie die ebenfalls noch nicht beschriebenen Zwischenstufen 6-10 sind im Vakuum unzersetzt destillierbare, nur wenig hydrolyseempfindliche Fliissigkeiten. Das Acetylsilanol 3 fie1 dagegen als kristalliner Feststoff an. 1-3 Das Acetylsilanol 3 kristallisiert als Racemat in der zentrosymmetrischen Raumgruppe P'i rnit zwei Molekiilen in der Elementarzelle. Bestimmend fur den Aufbau des Kristalls ist die Gliederung in polare und unpolare Bereiche
Zeitschrift Fur Anorganische Und Allgemeine Chemie, 2001
Inhaltsu È bersicht. Bei Untersuchungen u È ber Alkali-Erdalkalifluoride konnte erstmals die Verbindung NaSrMg 2 F 7 durch eine Fa È llungsreaktion von Sr 2+ , Mg 2+ und Na + mit F ± hergestellt werden. Sie fa È llt phasenrein in Form mikrokristalliner kugelfo È rmiger Agglomerate mit einem Durchmesser voñ 0.25 lm an. Die Verbindung kristallisiert mit a = 10.4379(4) A Ê in der kubischen Raumgruppe Fd 3 m (Nr. 227). Auf Basis der Ro È ntgenbeugungsdaten wurde eine Rietveldanalyse durchgefu È hrt. In Ûbereinstimmung mit der Strukturanalyse belegen spektroskopische Untersuchungen die Anwesenheit von zwei kristallographisch unterschiedlichen, gekoppelten Fluoridionen. Die Kristallstruktur entspricht dem bekannten Pyrochlortyp A 2 B 2 X 7 , wobei die A-Pla È tze statistisch zu je 50% mit Sr 2+ und Na + besetzt sind.
Zeitschrift für Naturforschung B, 1993
The zwitterionic A5-spirosilicates bis[1,2-benzenediolato(2–)][(morpholinio)methyl]silicate (1), bis[2,3-naphthalenediolato(2–)][(morpholinio)methyl]silicate (2; isolated as 2 • CH3CN), bis[1,2-benzenediolato(2–)][3-(morpholinio)propyl]silicate (3) and bis[2,3-naphthalenediolato(2 –)][3-(morpholinio)propyl]silicate (4; isolated as 4·1/2CH3CN) have been synthesized by various methods including Si – C bond cleavage reactions. The crystal structures of 2 • CH3CN and 4 · 1/2 CH3CN have been determined. 1,2 • CH3CN, 3 and 4 · 1/2 CH3CN have also been characterized by solution-state (1H, 13C, 29Si) and solid-state NMR spectroscopy (29Si CP/MAS). The pentacoordinate silicon atoms of the zwitterions 1-4 are surrounded by four oxygen atoms and one carbon atom. In the crystal, the coordination polyhedra around the silicon atoms of 2 • CH3CN (two crystallographically independent zwitterions and two crystallographically independent acetonitrile molecules) can be described as nearly ideal trigon...
Natrium-tetrathylammonium-tetrasulfid, Na+NEt4+S42−. Synthese und Kristallstruktur
1992
NaNEt 4 S 4 was obtained from an equimolar solution of Na 2 S 4 and NEt 4 Cl in ethanol. Its crystal structure was determined by X-ray diffraction with 4175 observed unique reflexions, R = 0.044. Crystal data: a = 713.4(4), b = 1744.5(9), c = 1204.0(5) pm, β = 105.8(3)°, space group P2 1 /n, Z = 4. In the structure, chains consisting of Na + and S 4 2#75 ions run in the a direction, every Na + being coordinated by four terminal S atoms of S 4 2#75 ions. The chains are separated by the NEt 4 + ions
Zeitschrift für anorganische und allgemeine Chemie, 2001
Professor Wolfgang Jeitschko zum 65. Geburtstag gewidmet Inhaltsu È bersicht. Die vier Verbindungen Er 6 [Si 11 N 20 ]O, Yb 6,081 [Si 11 N 20,234 ]O 0,757 , Dy 0,33 Sm 6 [Si 11 N 20 ]N und Nd 7 -[Si 8 Al 3 N 20 ]O der allgemeinen Formel Ln (6+x/3) -[Si (11±y) Al y N (20+x±y) ]O (1±x+y) (0 £ x £ 3, 0 £ y £ 3) wurden dargestellt. Die Synthese erfolgte in einem Hochfrequenzofen zwischen 1300 und 1650°C. Die Nitridosilicate kristallisieren trigonal mit folgenden Gitterkonstanten: Er 6 [Si 11 N 20 ]O: a = 978,8(4) pm, c = 1058,8(3) pm; Yb 6,081 [Si 11 N 20,243 ]O 0,757 : a = 974,9(1) pm, c = 1055,7(2) pm; Dy 0,33 Sm 6 [Si 11 N 20 ]N: a = 989,8(1) pm, c = 1078,7(1) pm; Nd 7 [Si 8 Al 3 N 20 ]O: a = 1004,25(9) pm, c = 1095,03(12) pm. Die homo È otypen Kristallstrukturen aller vier Verbindungen wurden aus Einkristalldaten gelo È st und in der Raumgruppe P31c mit Z = 2 verfeinert. Die Strukturen sind aus dreidimensionalen Netzwerken eckenverknu È pfter SiN 4 -bzw. AlN 4 -Tetraeder aufgebaut. In den Hohlra È umen finden sich Ln 3+ -Kationen und isolierte O 2± -Anionen. Gema È û der allgemeinen Formel Ln (6+x/3) [Si (11±y) Al y N (20+x±y) ]O (1±x+y) wurde der zuvor von Woike und Jeitschko beschriebene Er 6 [Si 11 N 20 ]O-Strukturtyp erweitert. New Representatives of the Er 6 [Si 11 N 20 ]O Structure Type. High-Temperature Synthesis and Single-Crystal Structure Refinement of Ln (6+x/3) [Si (11±y) Al y N (20+x±y) ]O (1±x+y) with Ln = Nd, Er, Yb, Dy and 0 £ x £ 3, 0 £ y £ 3 Abstract. According to the general formula Ln (6+x/3) -[Si (11±y) Al y N (20+x±y) ]O (1±x+y) (0 £ x £ 3, 0 £ y £ 3) four nitridosilicates, namely Er 6 [Si 11 N 20 ]O, Yb 6.081 [Si 11 N 20.234 ]O 0.757 , Dy 0.33 Sm 6 [Si 11 N 20 ]N, and Nd 7 [Si 8 Al 3 N 20 ]O were synthesized in a radiofrequency furnace at temperatures between 1300 and 1650°C. The homeotypic crystal structures of all four compounds were determined by single-crystal X-ray diffraction. The nitridosilicates are trigonal with the following lattice constants: Er 6 [Si 11 N 20 ]O: a = 978.8(4) pm, c = 1058.8(3) pm; Yb 6.081 [Si 11 N 20.243 ]O 0.757 : a = 974.9(1) pm, c = 1055.7(2) pm; Dy 0.33 Sm 6 [Si 11 N 20 ]N: a = 989.8(1) pm, c = 1078.7(1) pm; Nd 7 [Si 8 Al 3 N 20 ]O: a = 1004.25(9) pm, c = 1095.03(12) pm. The crystal structures were solved and refined in the space group P31c with Z = 2. The compounds contain three-dimensional networks built up by corner sharing SiN 4 and AlN 4 tetrahedra, respectively. The Ln 3+ and the ªisolatedº O 2± ions are situated in the voids of the structures. According to Ln (6+x/3) [Si (11±y) Al y N (20+x±y) ]O (1±x+y) an extension of the Er 6 [Si 11 N 20 ]O structure type has been found.