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1.
Meinhard Waburg Hanskarl Müller-Buschbaum 《Monatshefte für Chemie / Chemical Monthly》1986,117(2):131-138
For the first time Zn4V2O9 was prepared and investigated by single crystal X-ray methods. The metastable compound exists between a CO2-Laser generated flux and the solid ZnO/V2O5 material. The quenched light brown crystals show a monoclinic symmetry (space group C
2
2
—P21,a=10.488 (5),b=8.198 (6),c=9.682 (5) Å; =118.66 (4)°;Z=4]. Zn4V2O9 has a characteristic Zn/O-framework with incorporated V5+ in tetrahedral coordination. The relationship to Zn4Ta2O9 and the calculation of the madelung part of lattice energy (MAPLE) in respect to the metastable character are discussed. 相似文献
2.
About the New Compound Zn4Ta2O9 The hitherto unknown compound Zn4Ta2O9was prepared by high temperature reaction (CO2-LASER technique). The X-ray investigation of single crystal shows monoclinic symmetry (space group C? C2/c) with a = 15.002(6), b = 8.954(1), c = 10.345(4)Å and β = 93.64(3)°. Zn4Ta2O9 consists of a Zn/O-network with incorporated one-dimensional TaO6-chains. The edge connected TaO6-octahedrals are occupied by Ta5+ and 0.5 Zn2+ respectively. The crystal chemistry of this compound in respect to other Zn-oxotantalates are discussed. 相似文献
3.
Experiments about the Mixed Crystal Formation between Zincoxotantalates and -antimonates: ZnTa2?xSbxO6 and Zn4Ta2?xSbxO9 In the area of substituted oxotantalates of zinc two new phases of the composition A: ZnTa1·8Sb0·2O6 and B: Zn4Ta1·2Sb0·8O9 were prepared and investigated by X-ray single crystal technique. A crystallizes with tetragonal symmetry (space group D–P42/mnm, a = 4.7314; c = 9.2160 Å; Z = 2). B is monoclinic (space group C–C2/c; a = 15.103; b = 8.839; c = 10.378 Å; β = 93.81°; Z = 8). A crystallizes with trirutile structure, although there is a small replacement of Ta5+ by Sb5+. B maintains the Zn4Ta2O9 structure. One of the point positions of the M5+ ions is occupied statistically by Ta5+/Sb5+ and Zn2+. B is a metastable compound. 相似文献
4.
Ulrich Lehmann Hanskarl Müller-Buschbaum 《Monatshefte für Chemie / Chemical Monthly》1980,111(5):1225-1227
CoNb2O6 can be prepared by reaction of stoichiometric amounts of CoO (thermical decomposition of cobaltoxalate) and Nb2O5 in argon-atmosphere up to 1,400 °C. The isolated red-brown single crystals have tetragonal symmetry (a=472.6;c=305.4 pm; space group P42/mnm-D
4h
14
). Electron probe micro-analysis of the single crystals verifies the composition Co0.33Nb0.67O2. Co2+ and Nb5+ occupy statistically the metal positions of the rutil-type structure. The differences between Co0.5Nb0.5O2 (CoNbO4AlNbO4-type) and Co0.38Nb0.67O2 (CoNb2O6) are discussed. 相似文献
5.
Hans-Carsten Mumm Hanskarl Müller-Buschbaum 《Monatshefte für Chemie / Chemical Monthly》1987,118(12):1357-1362
Single crystals of -TlSm(WO4)2 were examined by X-ray diffractometer technique (space group C
2h
6
-C2/c;a=10.770,b=10.597,c=7.597 Å, =130.09°,Z=4). The coordination of W6+, Sm3+ and Tl+ are discribed and discussed.-TlSm(WO4)2 is isotypic to -KY(WO4)2. 相似文献
6.
The ordered double perovskites ALaMgTaO6 (A=Ba, Sr, Ca) and La2Mg(Mg1/3Ta2/3)O6 have been prepared and characterized. Synchrotron X-ray powder diffraction analyses show that all four compounds exhibit a rock-salt type ordering of the B-site cations (Mg2+/Ta5+) and a random distribution of A-site cations (A2+/La3+). The space group symmetries are determined to be for BaLaMgTaO6, and P21/n for SrLaMgTaO6, CaLaMgTaO6, and La2Mg(Mg1/3Ta2/3)O6. Diffuse-reflectance spectroscopy shows these ordered perovskites have optical band gaps in the range of 4.6−4.8 eV. These values are roughly 1 eV wider than the ternary perovskite oxides of Ta5+ such as KTaO3, due to narrowing of the conduction bandwidth which results from Mg2+/Ta5+ ordering. These compounds are insulators with dielectric permittivities of κ=18-23, dielectric losses of tan δ=0.004-0.007, and small temperature coefficients of capacitance <100 ppm/K over the temperature range 20-150 °C. BaLaMgTaO6 is of particular interest because it possesses a near-zero temperature dependence of capacitance. 相似文献
7.
Christoph Lang Hanskarl Müller-Buschbaum 《Monatshefte für Chemie / Chemical Monthly》1989,120(8-9):705-710
Summary The so far unknown compound Ba7Ir6O19 was prepared by long time solid state reactions using a flux of BaCl2. X-ray single crystal work lead to the space group C
2h
3
—C2/m;a=14.913;b=5.778;c=10.979 Å; =99.58°;Z=2. It crystallizes with a new structure type characterized by three face-shared octahedra. The Ir3O12-groups build up a threedimensional network with an incorporated Ba/O-frame. 相似文献
8.
Hansjörg Meyer Hanskarl Müller-Buschbaum 《Monatshefte für Chemie / Chemical Monthly》1981,112(1):51-57
Solid state reaction of CuO and Al2O3 with a flux of PbO about 930°C and reaction time of 8d gives the new compound Cu2Al4O7. The red single crystals were examined by energydispersive microanalysis and X-ray diffraction methods. Cu2Al4O7 has cubic symmetry, space group
,a=908.0 pm. The typical coordination of Cu+ (CN=6 and CN=12) and the interstitial arrangement of the AlO4-tetrahedra are discussed with respect to related compounds. 相似文献
9.
Gerald Giester 《Monatshefte für Chemie / Chemical Monthly》1989,120(8-9):661-666
Summary Single crystal X-ray data of the hydrothermally grown new phase Li2Cu3(SeO3)2(SeO4)2 were measured with a four-circle diffractometer up to sin /=0.81 Å–1 [I2/a,Z=4,V=1175.5 Å3,a=16.293(6),b=5.007(2),c=14.448(6) Å, = 94.21(1)°]. The structure was determined by direct and Fourier methods and refined toR=0.034,R
w
=0.027 for 2 086 independent reflections.Cu(1)[4+1]O5 forms a tetragonal pyramid, Cu(2)[4 + 2]O6 is a strongly elongated octahedron. The Li atom is surrounded by four O atoms forming a distorted tetrahedron. Se(IV)O3 and Se(VI)O4 groups are in accordance to literature, mean Se-O bond lengths are 1.714 and 1.644 Å.
Die Kristallstruktur von Li2Cu3(SeO3)2(SeO4)2
Zusammenfassung Einkristall-Röntgendaten der hydrothermal gezüchteten neuen Phase Li2Cu3(SeO3)2(SeO4)2 wurden mit einem Vierkreisdiffraktometer im Bereich bis zu sin /=0.81 Å–1 gemessen [I2/a,Z=4,V=1175.5 Å3,a=16.293(6),b=5.007(2),c=14.448(6) Å, =94.21(1)°]. Die Kristallstruktur wurde mittels direkter und Fourier-Methoden bestimmt und für 2 086 unabhängige Reflexe zuR=0.034,R w =0.027 verfeinert.Cu(1)[4+1]O5 bildet eine tetragonale Pyramide, Cu(2)[4+2]O6 ist ein stark verlängertes Oktaeder. Das Li-Atom ist von vier O-Atomen in Gestalt eines verzerrten Tetraeders umgeben. Die Se(IV)O3-und Se(VI)O4-Gruppen entsprechen der Literatur, die mittleren Se-O-Abstände betragen 1.714 und 1.644 Å.相似文献
10.
Zusammenfassung Wir untersuchten auf polarographischem Wege die Kinetik der Entladung von Zn2+ und Ni2+ an der Quecksilbertropfelektrode in einem Thiomalatmedium konstanter Ionenstärke (=0,5). Wir stellten fest, daß die Reduktion von Zn2+ und Ni2+ irreversibel verläuft und berechneten daher die kinetischen Parameter (Übertragungskoeffizient , Geschwindigkeitskonstante der HinreaktionK
f,h
o
) nach dem theoretischen Verfahren vonKoutecky in der vonMeites undIsrael erweiterten Form.
Mit 2 Abbildungen 相似文献
Kinetics of discharge of Zn2+ and Ni2+ at the D.M.E. in thiomalate media
Kinetics of discharge of Zn2+ and Ni2+ have been studied polarographically in thiomalate media of constant ionic strength (=0.5) at the dropping mercury electrode. The reduction of both Zn2+ and Ni2+ was found to be irreversible. Hence, the kinetic parameters (transfer coefficient , and forward rate constantK j,h o ) have been calculated byKoutecky's theoretical treatment as extended byMeites andIsrael.
Mit 2 Abbildungen 相似文献
11.
Hannelore Vinek H. Völlenkle H. Nowotny 《Monatshefte für Chemie / Chemical Monthly》1970,101(1):275-284
Zusammenfassung Die Kristallstruktur von Pb3GeAl10O20 und der dazu isotypen Verbindung Pb3SiAl10O20 wird bestimmt (R=0,16). Die Gitterparameter der monoklinen, pseudorhombischen Zelle (Raumgruppe I2/m–C
2h
3
;Z=2) sind:a=14,39;b=11,44;c=5,004 Å und =90,0 für Pb3GeAl10O20 und:a=14,34;b=11,39;c=4,96 und =90,0 für Pb3SiAl10O20. Das Gerüst besteht aus AlO4-Tetraedern und AlO6-Oktaedern, wobei Germanium und Aluminium statistisch über die Plätze 2b, 4h, 8j und 8j verteilt sind. Die Bleiatome sitzen in Kanälen parallel zu [001] in 2a und 4i. Die verschiedene Umgebung der Pb-Atome auf den beiden Plätzen wird diskutiert.
Mit 2 Abbildungen 相似文献
The crystal structure of Pb3GeAl10O20 (Pb3SiAl10O20)
The crystal structure of Pb3GeAl10O20 and Pb3SiAl10O20, an isotypic compound, has been determined (R=0.16). The lattice parameters were found to be:a=14.39 Å;b=11.44 Å;c=5.004 Å, and =90.0 for Pb3GeAl10O20 and:a=14.34 Å;b=11.39 Å;c=4.96 Å and =90.0 for Pb3SiAl10O20;Z=2, space group I2/m–C3 2h. The network consists of AlO4 tetrahedra and AlO6 octahedra; germanium atoms are randomly distributed at the positions of the Al-atoms 2b, 4h, 8j, and 8j. The lead atoms occupy the positions 2a and 4i within channels in the network parallel to [001]. The different environment of the two kinds of lead atoms will be discussed.
Mit 2 Abbildungen 相似文献
12.
On the Crystal Structure of Ba3In2Zn5O11. An Oxoindate/zincatesol;zincate with Zn10O20 and In4O16 Macropolyhedra with Zn2+ in Tetrahedral Coordination by O2? Ba3In2Zn5O11 was prepared for the first time by a flux technique and investigated by single crystal X-ray work. It crystallizes with cubic symmetry, space group T-F4 3m, a = 13.3588 Å, Z = 8. Zn2+ show tetrahedral coordination by O2?, forming Zn10O20 macropolyhedra. In addition the nZn/Osol;O part of the crystal structure is made up of Zn10O20 parts. Edge connection of four InO6 octahedra results in In4O16 groups. The crystal structure will be shown and discussed. 相似文献
13.
Rüdiger Brandt Hanskarl Müller-Buschbaum 《Monatshefte für Chemie / Chemical Monthly》1986,117(11):1239-1244
Solid state reaction of BaCO3, FeC2O4·2H2O and Nb2O5 gave single crystals of Ba6FeNb9O30. The crystal structure was solved by X-ray investigations (a=12.597,c=3.990Å, space group P 4 bm-C
4v
2
,Z=1). Ba6FeNb9O30 crystallyzes in the tetragonal bronze type with a statistical distribution of Fe3+ and Nb5+ in the octahedral framework. The anisotropic temperature factors of barium are discussed with respect to the oxygen coordination. 相似文献
14.
Johannes Reisch Raouf A. Hussain Bernt Krebs Mechtild Dartmann 《Monatshefte für Chemie / Chemical Monthly》1990,121(11):941-944
Summary C15H24O2,M=236.2, monoclinic, P 21,a=7.229(7),b=14.925 (9),c=6.235 (9) Å, =92.40 (9)°,V=672.1 Å3,T=–133 °C,Z=2,D
x=1.17 g cm–3. The X-ray diffraction analysis of this sesquiterpenoid fromCarissa opaca confirmed the previously proposed constitution of the isolate and, furthermore, allowed precise NMR assignment.
Naturstoffchemie, 100. Mitt.: Die Struktur des Carissons, C15H24O2
Zusammenfassung C15H24O2,M=236.2, monoklin, P 21,a=7.229 (7),b=14.925 (9),c=6.235 (9) Å, =92.40 (9)°,V=672.1 Å3,T=–133 °C,Z=2,D x=1.17 g cm–3. Die Röntgenstrukturanalyse dieses Sesquiterpenoids ausCarissa opaca bestätigte die bereits vorgeschlagene Struktur und erlaubte ferner eine genaue NMR-Zuordnung.相似文献
15.
Zusammenfassung Der Einbau von Fremdionen in -Al2O3 wurde mittels Reflexionsspektroskopie untersucht. Als Kristallfeldindikator wurde Cr3+ verwendet. Um den Einfluß tetraedrisch koordinierter Kationen auf das Chromspektrum zu untersuchen, wurde Zn2+, Cd2+, Ga3+ und Ge4+ zusätzlich eingebaut. Der Einfluß oktaedrisch koordinierter Kationen wurde an Cr3+ und Sn4+ untersucht. Aus der Verschiebung des Chromspektrums durch den Einbau von Ca2+, Sr2+ und Ba2+ in -Al2O3 wurde die Art des Einbaues dieser Kationen bestimmt und der Mechanismus einer Stabilisierung von -Al2O3 durch Einbau von Fremdionen diskutiert.
Mit 7 Abbildungen
H. Krischner, K. Torkar, R. Hoffmann undD. Donnert,4. Mitt., Mh. Chem.99, 1080 (1968). 相似文献
Reflection spectroscopy has been used to investigate the incorporation of foreign ions into -Al2O3, Cr3+ serving as a crystal field indicator. Zn2+, Cd2+, Ga3+ and Ge4+ where built in additionally to test the influence of tetrahedrally coordinated cations. The influence of cations with octahedral coordination was investigated by means of Cr3+ and Sn4+. The shift in the chromium spectrum observed after the incorporation of Ca2+, Sr2+ and Ba2+ was used to determine the type of incorporation. A mechanism of stabilisation of -Al2O3 after introduction of foreign ions is discussed.
Mit 7 Abbildungen
H. Krischner, K. Torkar, R. Hoffmann undD. Donnert,4. Mitt., Mh. Chem.99, 1080 (1968). 相似文献
16.
The crystal structure of lithium enneagermanate, Li4[Ge9O20], has been determined and refined by least-squares, using three-dimensional single-crystal data. The compounds crystallizes with monoclinic symmetry (a=12.43,b=8.00,c=7.49 Å, =91.0o; C2–C2
3) building up a framework structure which exhibits some similarity with the structures of Li2[Ge4O9] and Li2[Ge7O15]. Out of the 18 Ge-atoms in the unit cell 14 are surrounded tetrahedrally by oxygen showing an average distance of 1.757 Å; the remaining 4 Ge-atoms are octahedrally coordinated with an average distance of 1.886 Å.
Mit 3 Abbildungen
Herrn Professor Dr.O. Hromatka zum 65. Geburtstag gewidmet. 相似文献
Die Kristallstruktur des Lithium-enneagermanats Li4[Ge9O20]
Zusammenfassung Die Kristallstruktur von Lithium-enneagermanat Li4[Ge9O20] wird an Hand dreidimensionaler Einkristalldaten ermittelt und nach der Methode der kleinsten Quadrate verfeinert (R=0,083). Die monoklin kristallisierende Verbindung (a=12,43;b=8,00;c=7,49 Å; =91,0o; C2–C2 3) besitzt eine Gerüstruktur, die einen ähnlichen Aufbau wie Li2[Ge4O9] und Li2[Ge7O15] zeigt. Von den 18 Ge-Atomen in der Elementarzelle liegen 14 in tetraedrischer Koordination mit einem mittleren Ge–O-Abstand von 1,757 Å vor; 4 Ge-Atome sind oktaedrisch umgeben, mit einem mittleren Ge–O-Abstand von 1, 1886 Å.
Mit 3 Abbildungen
Herrn Professor Dr.O. Hromatka zum 65. Geburtstag gewidmet. 相似文献
17.
J. Kropiwnicka 《Journal of Thermal Analysis and Calorimetry》1990,36(3):979-990
In the ternary system La2O3-P2O5-Na2O the partial system La2O3-Na4La2P4O15-LaPO4 has been examined by the thermal, dilatometric X-ray and microscopic analyses and its phase diagram provided. The lanthanum oxyphosphate La3PO7 melts incongruently at the 1590°C temperature and crystallizes in a monoclinic systema=11.20 Å,b=11.94 Å,c=7.01 Å,=93.79 andV=936.97 Å3.
The author thanks Mrs. B. Lagódka for the technical assistance (thermogravimetric analyses). The thermal study was supported by grant CPBP. 相似文献
Zusammenfassung Mittels Thermo- und dilatometrischer Analyse, Röntgendiffraktionsuntersuchungen und Mikroskopie wurde das Teilsystem La2O3 - Na4La2P4O15 - LaPO4 des ternären Systemes La2O3 - P2O5 - Na2O untersucht und ein Phasendiagramm entwickelt. Lanthanoxyphosphat La3O7 schmilzt inkongruent bei 1590°C und kristalliert in einem monoklinen System mita=11.20 Ä,b=11.94 Ä,c=7.01 Å,=93.79 undV=936.97 Å3.
The author thanks Mrs. B. Lagódka for the technical assistance (thermogravimetric analyses). The thermal study was supported by grant CPBP. 相似文献
18.
R. Gruehn 《Monatshefte für Chemie / Chemical Monthly》1965,96(6):1789-1792
Zusammenfassung Bei Untersuchungen im WO3-ärmeren Bereich der Systeme Nb2O5-WO3 und Ta2O5-WO3 bis zum Molverhältnis Me2O5:WO3=1:2 wurden folgende Phasen neu gefunden: 40 Nb2O5·WO3–20 Nb2O5·WO3 (Phasenbreite), 13 Nb2O5· ·4 WO3, 9 Nb2O5·8 WO3 (Tieftemperaturphase), 9 Ta2O5· ·8 WO3; ferner eine Mischphase des T-Ta2O5, die bis zur Zusammensetzung 13 Ta2O5·4 WO3 (bei 1300° C) reicht. Weitere Phasen wurden im System Nb2O5-WO3 bei den Molverhältnissen 8:1–6: 1, 7:3, 8:5 und 9:8 (Hochtemperaturphase) beobachtet.49. Mitt.:H. Schäfer, R. Gruehn undF. Schulte, Angew. Chemie, im Druck. 相似文献
19.
Zusammenfassung Die Kristallstruktur der Verbindung Rb6Si10O23 (bisher als Rb2Si4O9 beschrieben) wurde mit Hilfe dreidimensionaler Röntgendaten bestimmt und bis zu einemR-Wert von 0,078 verfeinert. Die Gitterparameter der rhombischen Elementarzelle (C2mm-C
2v
14
) betragen:a=9,348,b=16,290 undc=8,055 Å. Die Struktur besitzt ein dreidimensionales Gerüst aus [SiO4]-Tetraedern, die sowohl über 4 als auch über 3 Ecken vernetzt vorliegen. Die Anordnung der Tetraeder kann aus der Tridymitstruktur abgeleitet werden und zeigt noch deutlich pseudohexagonale Symmetrie. Bei 500 °C geht die Verbindung in eine Hochtemperaturform mit hexagonaler Symmetrie über (a=9,48 undc=8,16 Å bei 500 °C).
Mit 3 Abbildungen 相似文献
The crystal structure of Rb6Si10O23
The crystal structure of the compound Rb6Si10O23 (identical with Rb2Si4O9) has been determined by means of three-dimensional X-ray data resulting anR-value of 0.078. The lattice parameters of the orthorhombic unit cell (C2mm-C 2v 14 ) are:a=9.348,b=16.290 andc=8.055 Å. The structure consists of a three-dimensional framework built up by [SiO4] tetrahedra sharing 4 as well as 3 corners. The arrangement of tetrahedra can be derived from tridymite structure and exhibits pseudohexagonal symmetry. The compound transforms to a high-temperature modification with hexagonal symmetry at 500 °C (a=9.48 andc=8.16 Å).
Mit 3 Abbildungen 相似文献
20.
S.Ya. Istomin S.V. Chernov Yu.A. Dobrovolsky 《Journal of solid state chemistry》2007,180(6):1882-1888
Novel complex oxides Ca14Zn6Ga10O35 and Ca14Zn5.5Ga10.5O35.25 were prepared in air at 1200 °C, 72 h. Refinements of their crystal structures using X-ray powder diffraction data showed that Ca14Zn6Ga10O35 is ordered (S.G. F23, =0.0458, Rp=0.0485, Rwp=0.0659, χ2=1.88) and Ca14Zn5.5Ga10.5O35.25 disordered (S.G. F432, =0.0346, Rp=0.0601, Rwp=0.0794, χ2=2.82) variants of the crystal structure of Ca14Zn6Al10O35. In the crystal structure of Ca14Zn6Ga10O35, there are large empty voids, which could be partially occupied by additional oxygen atoms upon substitution of Zn2+ by Ga3+ as in Ca14Zn5.5Ga10.5O35.25. These oxygen atoms are introduced into the crystal structure of Ca14Zn5.5Ga10.5O35.25 only as a part of four tetrahedra (Zn, Ga)O4 groups sharing common vertex. This creates a situation where even a minor change in the chemical composition leads to considerable anion and cation disordering resulting in a change of space group from F23 (no. 196) to F432 (no. 209). 相似文献