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  • 1
    Electronic Resource
    Electronic Resource
    Preparation and growth of (Bi,Pb)-Sr-Ca-Cu-O superconductor fibers (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 1032-1034 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The laser floating zone (LFZ) method has been used to grow (Bi,Pb)-Sr-Ca-Cu-O superconductor fibers from solution-derived ceramic precursors (nominal Bi1.8Pb0.35Sr1.87Ca2Cu3Ox), prepared under different sintering conditions. The as-grown LFZ fibers were semiconducting. After annealing at 855 and 800 °C in air, the fibers were metallic. A second anneal at these temperatures optimized the superconducting properties of the fibers [Tc (midpoint)=111 K and Tc (zero)=106 K]. The LFZ-grown fibers contain highly oriented superconductor grains their electrical properties depend strongly on precursor thermal processing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102455
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  • 2
    Electronic Resource
    Electronic Resource
    Ternäre Nitridoborate. 1. LiMg[BN2] und Ba4[BN2]2O, Verbindungen mit dem Anion [N—B—N]3-: Darstellung, Kristallstrukturen und Schwingungsspektren (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 18-24 
    Details
    ISSN: 0044-2313
    Keywords: LiMg[BN2] ; Ba4[BN2]2O ; Nitridoborates ; Linear Anions [BN2]3- ; Crystal Structure ; Vibrational Spectrum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ternary Nitridoborates. 1. LiMg[BN2] and Ba4[BN2]2O, Compounds with the Anion [N—B—N]3-: Syntheses, Crystal Structures, and Vibrational SpectraLiMg[BN2] and Ba4[BN2]2O were synthesized from stoichiometric mixtures of the binary components Li3N, Mg3N2, BN and BaO, Ba3N2. BN in sealed niobium ampoules at 1575 and 1350 K, respectively. The structures are characterized by isolated anions [N—B—N]3-, packed in different ways (LiMg[BN2]: I4/mmm (No. 139); a = 379.8 pm, c = 891.6 pm, c/a = 2.348; Z = 2; Ba4[BN2]2O; Cmca (No. 64); a = 1575.3 pm, b = 729.1 pm, c = 731.9 pm; Z = 4). The bond lengths and the bond angles are d(B—N) = 133.6 pm and β(N—B—N) = 180° in LiMg[BN2] and d(B—N) = 135 pm and β(N—B—N) = 173.4° in Ba4[BN2]2O, respectively.The vibrational spectra have been interpreted with respect to the D∞h symmetry of the isolated [N—B—N]3- anions, taking into account the slight symmetry reduction to C2v in Ba4[BN2]2O. The calculated valence force constants f(B—N) = 8.16 Ncm-1 and f(B—N) = 7.55 Ncm-1 are discussed and compared with those of other nitridoborates.
    Notes: LiMg[BN2] und Ba4[BN2]2O bilden sich aus stöchiometrischen Gemengen der binären Komponenten Li3N, Mg3N2, BN bzw. BaO, Ba3N2, BN in verschweißten Nb-Ampullen bei 1575 bzw. 1350 K. Die charakteristischen Bauelemente sind isolierte [N—B—N]3- -Anionen, die im Kristall unterschiedlich gepackt sind (LiMg[BN2]: I4/mmm (Nr. 139); a = 379.8 pm, c = 891.6pm, c/a = 2.348; Z = 2; Ba4[BN2]2O: Cmca (Nr.64); a = 1575.3 pm, b = 729.1pm, c = 731.9 pm; Z = 4). Die Bindungslängen und Bindungswinkel betragen d(B—N) = 133.6 pm und β(N—B—N) = 180° in LiMg[BN2] bzw. d(B—N) = 135 pm und β(N-B-N) = 173.4° in Ba4[BN2]2O.Die Schwingungsspektren der Verbindungen wurden auf der Basis der D∞h-Symmetrie der isolierten [N—B—N]3--Anionen unter Berücksichtigung der Symmetrieerniedrigung nach C2v in Ba4[BN2]2O interpretiert. Die aus den gemessenen Frequenzen berechneten Kraftkonstanten f(B—N) = 8.16 bzw. 7.55 Ncm-1 werden diskutiert und mit denen anderer Nitridoborate verglichen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230104
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  • 3
    Electronic Resource
    Electronic Resource
    Dipotassium Sodium Diantimonidoindate, K2Na[InSb2], a compound with the polyanion ∞2[In2Sb2Sb4/2]6- (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1717-1720 
    Details
    ISSN: 0044-2313
    Keywords: Dipotassium Sodium Diantimonidoindate ; K2Na[InSb2] ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dikalium-Natrium-Diantimonidoindat, K2Na[InSb2], eine Verbindung mit dem Polyanionen ∞2[In2Sb2Sb4/2]6-.Die neuartige Verbindung K2Na[InSb2] bildet sich aus den Elementen bei 900 K in geschlossenen Niobampullen als silbrig glänzende plättchenförmige Kristalle. Die Verbindung ist sehr empfindlich gegen Luft und Feuchtigkeit. Die Kristallstruktur von K2NaInSb2 (Raumgruppe Cmca, No. 64, a = 14,032(2), b = 16,399(3), c = 7,009(1) Å; Z = 8; Pearsonsymbol oC48) wurde an Einkristallen bestimmt. Die Struktur enthält Paare kantenverknüpfter InSb4-Tetraeder, welche über gemeinsame Ecken zu einer zweidimensionalen anionischen infin;2[In2Sb2Sb4/2]6--Teilstruktur verknüpft sind. Die resultierenden Paare tetraedrischer Lücken sind mit Na-Kationen gefüllt. Die [In2Sb2Sb4/2]6--Schichten sind entlang der b-Achse über K-Kationen miteinander verbunden. Die gesamte Struktur kann als Ordnungsvariante der KMnP-Struktur (PbFCl-Typ) angesehen werden.
    Notes: The novel compound K2Na[InSb2] was synthesized from the elements at 900 K in sealed niobium ampoules. The compound forms plate-like crystals with silver metallic luster, which are very unstable in air and moisture. The crystal structure of K2NaInSb2 has been determined using single-crystal X-ray diffraction methods (space group Cmca (No. 64); a = 14.032(2), b = 16.399(3), c = 7.009(1) Å; Z = 8; Pearson symbol oC48). The structure contains pairs of edge-sharing InSb4 tetrahedra which are linked to four other pairs via common vertices and form a two-dimensional ∞2[In2Sb2Sb4/2]6- anionic partial structure. The resulting pairs of tetrahedral holes are filled by Na+ cations. These [In2Sb2Sb4/2]6- layers are stacked along the b-axis and are interconnected by K+ cations. The whole structure can be considered as an ordered derivative of the KMnP structure (PbFCl type).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936191015
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  • 4
    Electronic Resource
    Electronic Resource
    K3Na26In48: An Intermetallic Phase with Large Pseudo-icosahedral Clusters and a Na46 Clathrate-I Network Enveloping a Covalent ∞3[In12] Cluster FrameworkDedicated to Professor Hartmut Bärnighausen on his 60th Birthday (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1556-1563 
    Details
    ISSN: 0044-2313
    Keywords: Indium Cluster Framework ; clathrate-I ; K3Na26In48 ; Synthesis ; Crystal Structure ; Properties ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: K3Na26In48: Eine intermetallische Phase mit großen pseudo-ikosaedrischen Clustern und einem Clathrat-I-Netz Na46, welches ein kovalentes Clusternetz ∞3[In12] einhülltK3Na26In48 bildet sich aus den Elementen in Form silberglänzender, spröder Kristalle in geschlossenen Niobampullen (aufgeschmolzen bei 873 K; getempert bei 573 K). Die Verbindung ist metallisch und sehr empfindlich gegen Luft und Feuchtigkeit. Die Kristallstruktur von K3Na26In48 (kubisch; Raumgruppe Pm3n, No. 223; a = 16,046(2) Å; Z = 2; Pearsonsymbol cP154) enthält Pro Elementarzelle zwei leere ikosaedrische In12ico-Cluster und sechs hexagonal-antiprismatische In12hap-Cluster mit einem Na-Atom im Zentrum. Sämtliche In12-Cluster sind durch je 12 kovalente Exo-Bindungen zu einem 3 D-Netz miteinander verbunden (In - In = 2,912 - 3,149 Å). Die übrigen Na-Atome bilden ein Na46-Netz vom Clathrat-I-Typ, dessen (2 + 6) Käfige die In12-Cluster einhüllen. Die neuartige Struktur kann als aufgefüllte Clathrat-I-Struktur angesehen werden: in der die [NaIn12hap]-Cluster durch K-Atome zu eindimensionalen Säulen verknüpft sind. Die K-Atome bilden auch ein (6,4)-Netz vom NbO-Typ mit Na-Atomen auf den Brückenpositionen. Die gesamte Struktur kann andererseits auch als kubisch-raumzentrierte Packung großer, mehrschaliger, kondensierter A122-Cluster von nahezu perfekter Ikosaedersymmetrie angesehen werden (Durchmesser 16 Å). Bindungsverhältnisse und strukturelle Zusammenhänge mit anderen Phasen werden eingehend diskutiert.
    Notes: K3Na26In48 was synthesized from the elements in sealed niobium ampoules (melted at 873 K; annealed at 573 K). The compound forms brittle crystals with silver metallic lustre, behaves as a metallic conductor, and is very sensitive to air and moisture. The crystal structure of K3Na26In48 (cubic; space group Pm3n,No. 223; a = 16.046(2) Å; Z = 2; Pearson symbol cP154) contains two empty icosahedral In12ico and six hexagonal antiprismatic In12hap indium clusters per unit cell. The latter are centered by Na atoms. All In12 clusters are interconnected by 12 exo-bonds forming a covalent 3 D network (In - In = 2.912 - 3.149 Å). The remaining Na atoms form a Na46 3 D-network of the clathrate-I type with (2 + 6) cages, enveloping the In12 clusters network. This novel structure can be regarded as a filled derivative of the clathrate-I structure: . The potassium atoms link the filled [NaIn12hap] clusters to 1 D columns, and also form (6,4) net of the NbO type with Na atoms at bridging positions. The whole structure can also be described as a bcc packing of huge condensed A122 clusters (16 Å diameter) which have nearly icosahedral symmetry and consist of several atomic shells. The bonding as well as the structural relationships to other phases are discussed in detail.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190910
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  • 5
    Electronic Resource
    Electronic Resource
    Crystal Structure and Vibrational Spectrum of Dipotassium Manganese(II) Hexathiodiphosphate(IV), K2Mn[P2S6] (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 1081-1086 
    Details
    ISSN: 0044-2313
    Keywords: K2Mn[P2S6], Hexathiodiphosphate(IV) ; Hexathiohypodiphosphate ; Crystal Structure ; Vibrational Spectrum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Kristallstruktur und Schwingungsspektrum von Dikaliummangan(II)-hexathiodiphosphat(IV), K2Mn[P2S6]K2Mn[P2S6] wurde aus den Elementen bei 1 173 K in evakuierten Quarzampullen dargestellt. Die Verbindung bildet transparente, hellbraune, luft- und feuchtigkeits-beständige Kristalle. Die Kristallstruktur von K2Mn[P2S6] (monoklin; Raumgruppe P21/n, No. 14; a = 6,1966(9), b = 12,133(2), c = 7,424(1) Å, β = 101,52(1)°; Z = 2; Pearson-Code mP22) enthält Säulen flächenverknüpfter S6-Polyeder (verzerrte Oktaeder und trigonale Antiprismen), die parallel zur a-Achse verlaufen und durch K+ (KZ 10; d(K—S) = 3,23-3,92 Å) miteinander verbunden sind. Die S6-Polyeder der Säulen werden alternierend durch Mn (in Oktaedern mit d̄(Mn—S) = 2,647 Å) bzw. P2-Paare (in trigonalen Antiprismen) zentriert, die zur a-Achse um 73,1° geneigt sind. Die Bindungslängen in den Hexathiodiphosphat(IV)-Anionen [P2S6]4- mit angenäherter 3 2/m-D3d-Symmetrie betragen d̄(P—P) = 2,211 und d̄(P—S) = 2,018 Å. K2Mn[P2S6] ist isotyp zu K2Fe[P2S6] und der zweite Vertreter dieses Strukturtyps. Die beobachteten Fundamentalschwingungen von K2Mn[P2S6] stehen im Einklang mit der Faktorgruppenanalyse und werden auf der Basis von [P2S6]4--Einheiten unter Berücksichtigung der Abweichung von der D3d-Symmetrie zugeordnet.
    Notes: K2Mn[P2S6] was synthesized from the elements in sealed quartz ampoules at 1 173 K. The compound forms transparent light brown crystals, stable against air and moisture. The crystal structure (monoclinic; space group P21/n, No. 14; a = 6.1966(9), b = 12.133(2), c = 7.424(1) Å, β = 101.52(1)°, Z = 2; Pearson code mP22) consists of columns of face-sharing S6 polyhedra (distorted octahedra and trigonal antiprisms) parallel to the a axis, interconnected by inserted K+ (CN 10; d(K—S) = 3.23-3.92 Å). The S6 polyhedra of the columns are centered alternately by Mn (in octahedra with d̄(Mn—S) = 2.647 Å) and P2 pairs (in trigonal antiprisms) which are inclined to the a axis by 73.1°. The bond lengths in the resulting hexathiodiphosphate(IV) anions, [P2S6]4-, with approximate 3 2/m-D3d symmetry, are d(P—P) = 2.211 Å and d(P—S) = 2.018 Å. K2Mn[P2S6] is isotypic to K2Fe[P2S6], being the second member of this structure type. The internal modes of the observed Raman and FIR/IR spectra of K2Mn[P2S6] are in accord with the factor group analysis, and the fundamentals are assigned on the basis of [P2S6]4- units, taking into account the deviation of the D3d symmetry.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200622
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  • 6
    Electronic Resource
    Electronic Resource
    Crystal structure and vibrational spectrum of copper mercury ortho-thiophosphate CuHgPS4 (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 4 (1993), S. 393-398 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The compound CuHgPS4 crystallizes in the orthorhombic system, space group Pna21 (No. 33), Z = 4, with lattice parameters a = 12.660(3), b = 7.3498(7), c = 6.0943(4) Å, and δcalc = 4.96 g/cm3. The title compound is stable in air and moisture and behaves as a semiconductor. The crystal structure consists of discrete tetrahedral PS43- anions joined together by Cu+ and Hg2+ cations. The arrangement of the sulfur atoms is approximately hexagonal close-packed in which P, Cu, and Hg occupy tetrahedral sites. The PS4, HgS4, and CuS4 tetrahedra are slightly distorted with mean distances d(P-S) = 2.055, d(Hg-S) = 2.524, and d(Cu—S) = 2.320 Å, and 8% of the Hg atoms were found to be disordered, occupying interstitial tetrahedral sites. The title compound is isotypic to AgZnPS4 and can be considered to be a defect structure of Enargite (Cu3AsS4), which is a substitution derivative of the Wurtzite (ZnS) structure. The CuHgPS4 vibrational spectrum has been recorded. The internal modes experimentally observed are in accord with the factor group prediction. A tentative assignment of the vibrational frequencies is proposed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520040413
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis, Structure and Vibrational Spectra of Ba14InP11 (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1015-1023 
    Details
    ISSN: 0009-2940
    Keywords: Ba14InP11 ; Zintl phase ; Tetraphosphidoindate(III) anions ; Asymmetric [P3]7- polyanions ; Interpenetrating hierarchical frameworks ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ba14InP11 was prepared from the elements in a sealed stainless steel ampoule at 1345 K. The compound is black, brittle and very sensitive to air and moisture. Ba14InP11 crystallises in the tetragonal Ca14AlSb11 type (space group I41/acd, No. 142; a = 17.097 (2) Å, c, = 8, Pearson code tI208). The structure contains isolated P3-, linear [P3]7- and tetrahedral [InP4]9- anions. The X-ray structure analysis and the vibrational spectra show that the [P3]7- polyanion is strongly asymmetric with d(P-P) = 2.28 Å and 4.10 Å, corresponding to a [P2]4- dumbbell weakly coupled to a single p3- anion. The tetraphosphidoindate(III) anion [InP4]9- is slightly compressed along the 4 axis, with bond lenght d(In-P) = 2.71 Å. It is shown that the structure is hierarchically related to that of Cu2O, with two interpenetrating frameworks, in which the O and Cu atoms are replaced by condensed [InP4/2] tetrahedron and [BaP4P2/2] octahedra, respectively. Both frameworks are meso configured, containing alternate R and S fragments. The other Ba cations envelop the P6 octahedra and P3 triads forming condensed cubes, tetragonal antiprisms and bicapped trigonal prisms. Therefore, the structure also forms a heterogeneous framework of centred PBa8/2tap tetragonal antiprisms and BaBa8/2cub cubes, consisting of two interpenetrating enantiomorphic nets (R and S) similar to those in the cubic phase RhBi4.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290907
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  • 8
    Electronic Resource
    Electronic Resource
    K21-δNa2+δIn39 (δ = 2.8): A Cluster-Replacement Clathrate-II Structure with an Alkali Metal M136-NetworkProfessor Hans Bock zum 65. Geburtstag gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 247-257 
    Details
    ISSN: 0044-2313
    Keywords: Staffed Clathrate-II ; K21-δNa2+δIn39 ; Indium Cluster Framework ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: K21-δNa2+δIn39 (δ = 2.8): Eine Cluster-substituierte Clathrat-II Struktur mit einem M136-AlkalimetallnetzK21-δNa2+δIn39 mit δ = 2,82 wurde aus den Elementen in geschlossenen Niobampullen als silbrigglänzende, prismatische Kristalle dargestellt (aufgeschmolzen bei 973 K; getempert bei 623 K). Die Verbindung ist sehr empfindlich gegen Luft und Feuchtigkeit. Die Kristallstruktur von K21-δNa2+δIn39 (orthorhombisch, Raumgruppe Pnma; No. 62; a = 17,844(5) Å, b = 17,192(3) Å, c = 25,078(7) Å; Z = 4; Pearson-Code oP248; δ = 2,82 aus der Strukturverfeinerung) enthält pro Elementarzelle acht leere ikosaedrische In12ico - Cluster (Typ A mit 12 und Typ B mit 7 Exo-Bindungen) und vier von K zentrierte offene In15-Cluster (15 Exo-Bindungen), die Teile von C-Einheiten sind. Die C-Einheiten sind Heterocluster [K(Na2M3In15)] mit M = K + Na. Die räumliche Verteilung der In12ico-Ikosaeder A, B und der Heterocluster C entspricht der Atomverteilung in der kubischen Laves-Phase MgCu2: MgCu2 ≙ [K(Na2M3In15)][In12ico]2. Sämtliche Inn-Cluster sind durch kovalente Exo-Bindungen zu einem 3D-Netzwerk miteinander verbunden (d(In—In) = 2,832 - 3,301 Å). Die restlichen Alkalimetallatome bilden ein M136-Netzwerk vom Clathrat-II-Typ, dessen 16 + 8 Käfige die In12ico-Ikosaeder und [K(Na2M3In15)]-Cluster einhüllen. Die Struktur kann als eine Cluster-substituierte Clathrat-II-Struktur beschrieben werden: (H2)16(CCl4)8(H2O)136 ≙ [In12ico]16[K(M5In15)]8M136. Sie ist ein Vertreter einer neuartigen hierarchischen Strukturfamilie auf der Basis von Cluster-Substitution. Bindungsverhältnisse und strukturelle Zusammenhänge mit anderen Phasen werden diskutiert.
    Notes: K21-δNa2+δIn39 with δ = 2.82 was synthesized (melted at 973 K, annealed at 623 K) from the elements in sealed niobium ampoules. The compound forms prismatic crystals with silver metallic lustre and is unstable in air and moisture. The crystal structure of K21-δNa2+δIn39 (orthorhombic; space group Pnma, No. 62; a = 17.844(5) Å, b = 17.192(3) Å, c = 25.078(7) Å; Z = 4; Pearson code oP248; δ = 2.82, obtained from the structure refinement) contains eight empty In12ico icosahedra of two types, A (12 exo-bonds) and B (7 exobonds), and four open In15 clusters (15 exo-bonds). The latter are centered by K atoms and belong to C units, which are defined as [K(Na2M3In15)] heteroatomic clusters (M = K + Na). The spatial distribution of the In12ico icosahedra A, B and heteroatomic clusters C is that of the atoms in the cubic Laves phase MgCu2: MgCu2 ≙ [K(Na2M3In15)][In12ico]2. All the Inn clusters are interconnected by exo-bonds forming a covalent three-dimensional framework (d(In—In) = 2.832 to 3.301 Å). The remaining alkali metal atoms build up a three-dimensional M136 network of the clathrate-II type with (16 + 8) cages, which envelopes the In12ico icosahedra and [K(Na2M3In15)] clusters. This structure can be described as a cluster-replacement derivative of the clathrate-II structure: (H2S)16(CCl4)8 · (H2O)136 ≙ [In12ico]16[K(M5In15)]8M136, and is one member of a novel hierarchical structure family, based upon cluster-replacement. The bonding as well as the structural relationships to other phases are discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200208
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  • 9
    Electronic Resource
    Electronic Resource
    Hückel-Arene mit zehn π-Elektronen: Die cyclischen Zintl-Anionen Si610- und Ge610-, isoster mit P64- und As64- (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 108 (1996), S. 1062-1064 
    Details
    ISSN: 0044-8249
    Keywords: Elektronenlokalisierung ; Germaniumverbindungen ; Siliciumverbindungen ; Zintl-Phasen ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19961080911
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  • 10
    Electronic Resource
    Electronic Resource
    Tribarium tetrahedro-Tetragermanide Acetylenide, Ba3[Ge4][C2]: Synthesis, structure, and propertiesProfessor Walter Siebert zum 60. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 929-936 
    Details
    ISSN: 0044-2313
    Keywords: Ba3Ge4C2 ; Zintl Phase ; tetrahedro-Tetragermanide [Ge4]4- Anions ; Acetylenide [C2]2- Anions ; Vibrational Spectra ; Force Constants ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tribarium tetrahedro-Tetragermanid- Acetylenid, Ba3[Ge4][C2] - Synthese, Struktur und EigenschaftenBa3Ge4C2 bildet sich aus den Elementen order durch die Umsetzung von BaC2 mit BaGe2 bei 1530 K (korundtiegel in geschlossener Stahlampulle). Die Verbindung ist ein Halbleiter (grau; Eg = 1.1 eV), spröde, und sehr feuchtigkeitsempfindlich. Sie reagiert mit NH4Cl bei ca. 400 K unter Bildung von Acetylen und Germanen bis Ge4Hn. Der neue Ba3Ge4C2-Strukturtyp (Raumgruppe I4/mcm, No. 140; a = 8.840(1) Å, c = 12.466(1) Å; Z = 4, Pearsonsymbol tI36) enthält zwei isolierte Polyanionen, nämlich Tetrahedro-tetragermanid [Ge4]4- und Acetylenid [C2]2-. Die Bindungslängen betragen d(Ge—Ge) = 2.517 Å (4×) bzw. 2.641 Å (2x) und d(C≡C) = 1.20 Å. Die Struktur von Ba3[Ge4][C2] ist durch Atom/Cluster-Substitutionen ([Ge4] statt Ca; [C2] statt Ti; Ba statt O) eine hierarchische Variante der Perowskit-Struktur CaTiO3. Das Raman-Spektrum zeigt Banden bei 168, 199 und 280 cm-1 bzw. 1796 cm-1, die für die Polyanionen [Ge4]4- und [C2]2- charakteristisch sind.
    Notes: Ba3Ge4C2 is formed at 1530 K from the elements or by reaction of BaC2 with BaGe2 (corundum crucible; steel ampoule). The compound is a semiconductor (grey colour; Eg = 1.1 eV), brittle, very sensitive to moisture, and reacts with NH4Cl at about 400 K forming acetylene and germanes up to Ge4Hn. The new Ba3Ge4C2 structure type (space group I4/mcm, No. 140; a = 8.840(1) Å, c = 12.466(1) Å; Z = 4, Pearson code tI36), contains two kinds of isolated polyanions, namely tetrahedro-tetragermanide [Ge4]4- and acetylenide [C2]2- anions. The bond lengths are d(Ge-Ge) = 2.517 Å (4×) and 2.641 Å (2×), and d(C≡C) = 1.20 Å. The Ba3[Ge4][C2] structure is a hierarchical derivative of the perovskite (CaTiO3) generated by a partial atom/cluster replacement ([Ge4] for Ca, [C2] for Ti and Ba for O). The Raman spectrum shows bands at 168, 199 and 280 cm-1, and at 1796cm-1 characteristic for [Ge4]4- and [C2]2- polyanions, respectively.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301146
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