Search

Ba2(Ni1−xLix)Ni2N2 wird durch Umsetzung von Lithium-Barium-Schmelzen (molare Verhaltnisse Li : Ba zwischen 1 : 1 und 3 : 1) mit stromendem Stickstoff (1 atm.)) im Nickeltiegel bei 800°C und einer Reaktionsdauer von 15 h dargestellt. Durch Kuhlungskristallisation (Kuhlrate 10°C/h)) wird die Verbindung in Form schwarz-glanzender Einkristalle erhalten (orthorhombisch, Cmca; a = 713,3(2) pm, b = 1027,4(7)) pm, c = 752,2(4 pm; Z = 4; DRo = 5,50 g/cm3 bei x = 0,43)). Die Kristallstruktur enthalt parallel [100] verlaufende nahezu gestreckte Ketten [NiN2/2] (NNiN: 178,5(7°, NiNNi 173,4(7)°, NiN: 178,6(1)pm), die uber Substitutionslagen (Ni1−xLix) unter Ausbildung gestreckter Hanteln (N(Nix−1LixN) (Bindungslangen 194,5(12)pm, x = 0,43) zu gewellten Schichten [(NiN2/2)(Ni1−xLix)(NiN2/2)] verknupft werden Barium ist verzerrt trigonal-planar von Stickstoff umgeben (BaN: 281,1(11)pm − 285,5(11)pm). fur Stickstoff resultiert eine oktaedrische Koordination NBa3(Ni1−xLix)Ni2, mit Nickel in trans-Stellung. Die Kristallstruktur von Ba2(Ni1−xLix)Ni2N2 weist eine enge Verwandtschaft zum Li3N-Typ auf: Li2[LiN] ⟷ Ba{(Ni1−xLix)0,5 □ 0,5}[NiN]. Gleichzeitig wird durch sie das Spektrum von Anionenverbanden in Nitridoniccolaten des Bariums erweitert. Bisher waren bekannt: BaNiN (ebene [NiN2/2]-Zickzack-Ketten) und Ba8Ni6N7 ([NiN2/2]-Schrauben). Ba2(Ni1−xLix)Ni2N2: A Low-Valency Nitridoniccolate with Puckered Layers [(NiN2/2)(Ni1−xLix)(NiN2/2)] Ba2(Ni1−xLix)Ni2N2 is obtained by reaction of lithium-barium-melts (molar ratios Li : Ba between 1 : 1 and 3 : 1) with nitrogen (1 atm.) in nickel-crucibles within a period of 15 h. Single crystals with a dark-metallic lustre are formed by cooling the melt to room temperature with a rate of 10°C/h (orthorhombic, Cmca; a = 713.3(2)pm, b = 1027.4(7)pm, c = 752.2(4)pm; z = 4; Dxr = 5.50 g/cm3 with x = 0.43). The crystal structure contains nearly liner [NiN2/2]-chains (NNiN: 178.5(7)°, NiNNi 173.4(7)°; NiN: 178.6(1)pm), running parallel to the [100] direction, which are interconnected via (Ni1−xLix)-sites (linear units (N(Ni1−xLix)N); bond-lenths: 194.5(12)pm with x = 0.43) to form puckered layer [(Nin2/2)(Ni1−xLix)(NiN2/2)]. Barium is in a distorted trigonal-planar coordination by nitrogen atoms (BaN: 281.1(11)pm − 285.5(11)pm. The nitrogen-coordination corresponds to a distorted octahedron, NBa3(Ni1−xLix)Ni2, with nickel in trans-position. The crystal structure of Ba2(Ni1−xLix)Ni2N2 is closely related to the Li3N-type structure: Li2[LiN] ⟷ Ba{(Ni1−xLix)0.5 □ 0.5}[NiN]. Furthermore, this structure enlarges the scope of barium-nitrido-niccolates which up to now were found to contain merely [NiN2/2]-chains(BaNiN: Planar zigzag-chains; Ba8Ni6N7 helical zigzag-chains).

The isotypic ternary compounds Ba3[MoN4] and Ba3[WN4] were prepared by reaction of the transition metals with barium (Ba3N2, resp.) under nitrogen. The crystal structures were determined by single crystal X-ray diffraction: Ba3[MoN4] (Ba3[WN4]): Pbca; Z = 8; a = 1083.9(3) pm (1091.8(3) pm), b = 1030.3(3) pm (1037.5(3) pm), c = 1202.9(3) pm (1209.2(4) pm). The structures contain isolated tetrahedral anions [MN4]6- (M = Mo, W) which are arranged in form of slightly distorted hexagonal layers and which are stacked along [010] with the sequence (···AB···). Two of the three Ba atoms are situated between, the third one is placed within the layers of [MN4]-groups. In this way the structures can be derived from the Na3As structure type.

Isometrische, schwarz-glanzende Einkristalle von Li3Sr3Ni4N4 (orthorhombisch, Immm; a = 401,1(1) pm, b = 708,8(3) pm, c = 1663,0(8) pm; Z = 2) wurden in geschlossenen Nickelampullen durch Reaktion von Li4SrN2 mit dem Tiegelmaterial dargestellt (Aufheizraten 50°C/h; 20 h bei 800°C; Abkuhlrate 10°C/h). Die Kristallstruktur enthalt parallel [010] verlaufende [NiN]-Ketten (NiN: 177,3(1) pm und 177,8(1) pm). Lithium und Strontium sind in Ebenen (010) senkrecht zu den [NiN]-Ketten angeordnet und verknupfen diese uber die Stickstoffatome. Lithium ist zweifach (linear; LiN: 200,7(1) pm und 200,4(7) pm), Strontium ist sowohl verzerrt trigonal-planar (SrN: 264,5(5) pm und 268,0(7) pm) als auch planar-quadratisch (SrN: 277,6(6) pm) von Stickstoff koordiniert. Stickstoff selbst ist oktaedrisch von Ni, Li und Sr umgeben; die Koordinationsoktaeder NNi2Sr4 und NNi2Li3Sr werden uber gemeinsame Ecken und Kanten miteinander verknupft. Der insgesamt dreidimensionale Strukturverband enthalt eindimensionale (inverse) Fragmente der Oktaederstrukturen des ReO3- und Rutil-Typs. Li3Sr3Ni4N4: An Low-Valency Nitridoniccolate with [NiN]-Chains Isometric black-reflecting crystals of Li3Sr3Ni4N4 (orthorhombic, Immm; a = 401.1(1) pm, b = 708.8(3) pm, c = 1663.0(8) pm; Z = 2) were obtained by wall-reaction of Li4SrN2 in closed nickel tubes (heating rate 50°C/h; reaction at 800°C for 20 h; cooling rate 10°C/h). The crystal structure contains [NiN]-chains (NiN: 177.3(1) pm and 177.8(1) pm) which run parallel to the [010] direction. Lithium and strontium are arranged in planes (010) perpendicular to the [NiN]-chains and interconnect the chains via the nitrogen atoms. Lithium is in a two-fold (linear; LiN: 200.7(1) pm and 200.4(7) pm), strontium is in three-and four-fold (distorted trigonal-and square-planar) N-coordination (SrN: 264.5(5) pm, 268.0(7) pm and 277.6(6) pm, resp.). Nitrogen is in an octahedral surrounding by Ni, Li and Sr; the coordination-octahedra NNi2Sr4 and NNi2Li3Sr are condensed by sharing common edges and apices. The three-dimensional framework contains one-dimensional fragments of the (inverse) octahedral structures of the ReO3 and Rutile structure types.

We report here on the growth of large crystals of Gd-Ba-Cu-O superconductor by using the ‘K2CO3-method’ adopted earlier for preparing oriented ceramics and large crystals of Y-Ba-Cu-O superconductors. The temperature favourable for the growth of GdBaCuO crystals is found to be higher than that required for YBaCuO crystals. Also, the crystal perfection is better for these crystals and as a result, the oxygenation of the sample becomes more difficult. Resistivity measurements on these samples show a sharp drop in resistivity at 90 K which then tails off at lower temperatures and attains zero resistance around 35 K. Such behaviour is normally due to an inhomogeneous oxygen content in the sample. Chemical analysis shows that the deviation from ‘123’ composition in GdBaCuO-samples is much less as compared to YBaCuO-samples obtained by the same technique.

Ba8Ni6N7 was prepared from mixtures (pressed pellets) of BaNiN and Ba3N2 (molar ratio 1:1) at 800 °C under nitrogen. The crystal structure was determined by single-crystal X-ray diffraction ( C2 c ; a = 948.7(4) pm, b = 1657.8(6) pm, c = 1213.7(7) pm; β = 107.05(5)°; Z = 4). The rather complex new structure type is generated by distorted nitrogen coordination octahedra (NBa6, NBa4Ni2(cis) and NBa4Ni2(trans)) which share common edges as well as common corners. Barium is in a threefold (trig, planar) and a fourfold (distorted tetrahedral) nitrogen environment. Nickel (nearly linear coordination, N-Ni-N angle: 162.4(5)°–176.4(4)dg) and nitrogen (distance Ni[2]-N[6]: 175.6(10)–181.0(14) pm) are arranged to form infinite helical [Ni-N] zigzag chains which run parallel to the c ∗ direction.

Die isotypen Phasen Ca6GaN5 und Ca6GeN5 (hexagonal, P63/mem; a = 627, 7(3)/623,7(1) pm, c = 1219,8(3)/1233,2(6) pm; Z = 2) werden durch Reaktion von Gemischen aus Ca und Ga (molares Verhaltnis 6:1) bzw. Fe, Ca3N2 und Ca (molare Verhaltnisse zwischen 3:1:13 und 5:2:15) mit Stickstoff bei Temperaturen von 850°C bzw. 950°C bis 1100°C erhalten. Als wesentliche Strukturmerkmale treten carbonat-isostere, trigonal-planare Anionen [MN3]6− auf (GaN: 195,1(28) pm; FeN: 177,0(15) pm). Enge Verwandtschaft besteht zu den Kristallstrukturen von Verbindungen der Hydrotalkit-Gruppe. Ca6GaN5 and Ca6FeN5: Compounds Containing [CO3]2−-isosteric Anions [GaN3]6− and [FeN3]6− The isotypic phases Ca6GaN5 and Ca6FeN5 (hexagonal, P63/mem; a = 627.7(3)/ 623,7(1) pm, c = 1219.8(3)/1233.2(6) pm; Z = 2) are prepared by reaction of Ca/Ga mixtures (molar ratio 6:1) and Fe/Ca3N2/Ca mixtures (molar ratios from 3:1:13 to 5:2:15) with nitrogen at temperatures of 850°C and 950°C to 1100°C, respectively. The structures contain trigonal-planar anions [MN3]6− which are isosteric to carbonate ions (GaN: 195,1(28) pm; FeN: 177,0(15) pm). The structures are closely related to those compounds of the hydrotalcite group.

The advantage of using K 2 CO 3 or KCl as flux materials for material processing and crystal growth of RBa 2 Cu 3 O x ( R = Y , Gd , Dy , Pr , etc.) is reviewed. As far as their role in crystal growth is concerned, different possibilities are discussed. Large mosaic crystals with low misorientation can be obtained by using K 2 CO 3 or KCl as additives during synthesis. Preparation temperatures in the range of 1270–1330 K are important as well as the slow cooling process. Under defined conditions, it is possible to obtain potassium-free products. With the exception of the non-superconducting Pr compound all compounds exhibit a distinct platelet morphology. In contrast to Gd, Dy and Pr derivatives, Y derivative shows a considerable nonstoichiometry and antisite disorder in the R and Ba sublattices. While oxygenation of the Y-123 crystals is achieved with ease, it is extremely difficult for rare earth derivatives. After oxygenation, the Y derivatives show a fairly sharp transition to the superconducting phase whereas the Gd and Dy derivatives show a broad transition with a width of ∼50 K. The difficulties in the oxygenation of rare earth derivatives are attributed to the absence of significant antisite disorder.

Li3FeN2 was prepared from the melt under nitrogen and the crystal structure was determined by single-crystal diffraction (Ibam; a = 487.2(1) pm, b = 964.1(2) pm, c = 479.2(1) pm, Z = 4). The crystal structure can be described in terms of a fluorite superstructure which contains infinite chains 1 ∞ [FeN 4 2 3−] of edge-sharing FeN4 tetrahedra. Measurements of the magnetic susceptibilities vs. temperature reveal Curie-Weiss behaviour. Magnetic ordering occurs below 10 K. The calculated magnetic moment of 1.7(1) μB indicates a low spin state of the Fe3+ ion.

Single crystals of ternary and quaternary phases of the Li-Sr-Ni-N-system were grown from the melt under nitrogen and were investigated by X-ray diffraction methods. The crystal structures are classified into the following groups: i. solid solutions (substitutional type) of the Li 3 N-structure (Li 1−x Ni x [Li 2 N]), ii. structures containing fragments of the Li 3 N-structure (Li 4 SrN 2 , LiSrN and Li 4 Sr 2 (Li 0.8 .Ni 0.2 )N 3 and iii- structures which can be derived from interstitial binary metal nitrides of the first transition series (Li 3 Sr 3 Ni 4 N 4 ). The crystal structure of SrNiN is not quite clear at present, but shows close relations to the crystal structure of BaNiN (Sr(Ni 1−x Li x )N, resp.).

The ternary compounds were prepared by reaction of the transition metals with Li3N melt under nitrogen. The crystal structures of Li6MeN4 (P42/nmc, Z = 2; Me = Mo: a = 667.3(1) pm, c = 492.5(3) pm; Me = W: a = 667.9(1) pm, c = 492.7(1) pm) and Li15Cr2N9 (P4/ncc, Z = 4; a = 1023.3(5) pm, c = 938.9(7) pm) can be described as fluorite-type superstructures with the lithium and transition metal atoms in tetrahedral holes of the nearly fcc nitrogen arrangement and with an ordered distribution of defects within the cation substructure. In addition, the ternary system Li–Cr–N contains the compound Li6CrN4 with a crystal structure which is not quite clear at present, but which shows close relations to the structures of Li6MeN4 (Me = Mo, W). The previously reported compounds Li9MeN5 (Me = Cr, Mo, W) have not been observed during this study. The respective Cr compound in fact is a nitride-oxide (nitride-imide) of composition Li14Cr2N8(O,NH) with a crystal structure (P3̄, Z = 1, a = 579.9(1) pm, c = 826.3(6) pm) also showing a fluorite-type superstructure.

Stimulated by the concept of the possibility of a polarizable N3− ion and the potentiality of its being a fast Li-ionic conductor, lithium nitride, Li3N, has been, and still is, the subject of broad interdisciplinary investigations. These form an excellent example for modern solid state research. This paper will describe this situation and review the present state of this fast developing field.

The main features of an advanced Pulsed Field Gradient (PFG) NMR equipment for selective and precise determination of self diffusion coefficients in the liquid and solid state of ionic conductors is describted.

The proton conductivity in H3OUO2AsO4·3H2O (HUAs) has been measured below the transition temperature at 299 K. A consistent picture of the elementary process taking place is developed from separate electrochemical, spectroscopic and calorimetric measurements. The conductivity is proposed to occur by the “vehicle mechanism” of proton transport, i.e. the cooperative motion of H3O+ and H2O. This mechanism is compared with the Grotthuss and the simple ion hopping mechanism.

α- and β-AuSe crystallize in the space group C2 m with a = 12.202(2) and 8.355(2) A , b = 3.690(7) and 3.663(1) A , c = 8.433(2) and 6.262(1) A , β = 103.15(2) and 106.03(2) ° , respectively. Both modifications of AuSe contain Au+ and Au3+. Au+ is coordinated linearly to two Se atoms. Au3+ is surrounded by four Se atoms in the form of a planar square. These essential bonds form infinite rods parallel to the monoclinic b axis in α-AuSe and waved sheets parallel to (100) in β-AuSe. Rods and sheets are connected by weak Au-Au and Se-Se bonds in α-AuSe and by weak Au-Se bonds in β-AuSe.

Tl6PbJ10 bildet hexagonale metallisch glanzende Kristalle. Es schmilzt unter eigenem Joddruck bei 355°C. Im Vakuum oder Inertgasstrom zersetzt es sich oberhalb 180°C unter Abgabe von 1 Mol J2. Tl6PbJ10 kristallisiert in der Raumgruppe P62c mit den Gitterkonstanten a = 10,561 A, c = 13,522 A und Z = 2. Die Struktur- und Uberstrukturbestimmung ergab, das Tl6PbJ10 eine Tl6J6-Geruststruktur mit Kanalen parallel zur c-Achse bildet. Diese Kanale enthalten entweder Pb2+-Ionen, oder lineare, nahezu regelmasige J42−-Polyjodidionen. Preparation, Structure, and Superstructure Analysis of Tl6PbI10 Tl6PbI10 forms hexagonal crystals with metallic luster. Under its own I2-pressure the m.p. is 355°C. In vacuum or under inertgas Tl6PbI10 decomposes above 180°C forming 1 Mol I2. The space group is P62c with the lattice constants a = 10.561, c = 13.522 A and Z = 2. The structure and superstructure have been determined. Tl6PbI10 is built up by a framework of Tl6I6 with channels parallel to the c-axis. These channels contain either Pb2+ or linear and nearly regular I42−-polyiodide ions.

Uberfuhrungsmessungen an CaS zeigen eindeutig und auf direkte Weise, das zweiwertige Calciumionen die uberwiegend beweglichen Ladungstrager darstellen. Die Impedanz wurde im Frequenzbereich 10 Hz — 170 kHz als Funktion des Schwefelpartialdrucks von 10−1 bis 10−8 atm uber das Temperaturintervall 900—1300 K gemessen. Die Leitfahigkeit ist unabhangig vom Schwefelpartialdruck unterhalb etwa 10−5 atm und steigt mit der 6. Wurzel aus dem Schwefelpartialdruck bei hoheren Drucken an (1100—1300 K). Die Leitfahigkeit σ von CaS betragt bei 1000 K 3,9 · 10−6 ω−1 cm−1. Die Aktivierungsenthalpie von σ T ist 1,15 eV. Die Abhangigkeit der Leitfahigkeit vom Schwefelpartialdruck last sich durch die Annahme eines Schottky-Fehlordnungsmodells erklaren. Investigations of the Ionic Transport Properties in Solid CaS Transference measurements clearly indicate in direct manner the predominant motion of divalent Ca2+ ions in CaS. The ac impedance was measured as a function of the sulfur partial pressure in the range from 10−1 to 10−8 atm from 900 to 1300 K in the frequency range from 10 Hz to 170 kHz. The conductivity is independent of the sulfur partial pressure below about 10−5 atm and increases with the 6th root of the sulfur partial pressure at higher p (1100—1300 K). The conductivity σ of CaS is 3.9 · 10−6 ω−1 cm−1 at 1000 K. The activation enthalpy of σ T is 1.15 eV. The dependence of the conductivity from the sulfur partial pressure is explained in terms of a Schottky type defect model for CaS.

Kupfertellurbromid, CuTeBr, zeigt eine reversible sprunghafte Anderung in der elektrischen Leitfahigkeit. Nach calorischen Messungen liegt ein Phasenubergang erster Ordnung bei 345 K vor, mit ΔHu = 76,8 cal/g-Mol und ΔSu = 0,222 cal/g-Mol K. Nach Rontgenuntersuchungen ist der Ubergang mit einer sprunghaften Anderung der Gitterkonstanten und gleichzeitigem Verschwinden der — orthorhombischen — Uberstruktur verbunden. Einkristallbestimmungen der HT-Phase zeigen die tetragonale Hauptstruktur (Raumgruppe I 41/amd); gleichzeitig findet eine Umbesetzung der statistisch besetzten Kupferatomlagen statt. Die Ergebnisse werden auf der Basis einer displaziven Umwandlung diskutiert. Telluride Halides of Copper with High Ionic Partial Conductivity. III. On the Phase Transition of CuTeBr and the Structure of the High Temperature Phase Copper telluride bromide, CuTeBr, exhibits a reversible sudden change of the electric conductivity. From caloric data a first order phase transition at 345 K can be concluded with ΔHu = 76.8 cal/g-mol and ΔSu = 0.222 cal/g-mol K. X-ray measurements show a sudden change of the lattice parameters and the disappearance of the — orthorhombic — superstructure at the transition. Single crystal determinations of the HT-phase yield the tetragonal main structure (space group I 41/amd); simultaneously a rearrangement of the statistical population of the Cu sites is observed. The results are discussed on the basis of a displacive transition.

The phase equilibria of the quasi-binary systems Li3N-LiX (X ≡ Cl, Br, I) and the Gibbs phase triangles of the ternary systems Li-N-X are presented. Thermodynamic data related to the formation of the ternary lithium nitride halides are derived from electrochemical decomposition measurements. The ranges of lithium activities and halogen equilibrium partial pressures under which the compounds may exist are given. All compounds are stable against reaction with elemental lithium and nitrogen at atmospheric pressure. The standard enthalpy and entropy of Li9N2Cl3 at 298 K with respect to 0 K are −47.8 ± 0.7 kJ mol−1 and −284 ± 8 J mol−1 K−1 respectively. The heats of the phase transitions of Li13N4Br at 506 K and Li5NI2 at 450 K are 0.927 kJ mol−1 and 6.96 kJ mol−1 respectively. The new compound Li9N2Br3 crystallizes in a body-centred tetragonal structure with a = 11.761 A and c = 5.993 A .

Kristalle von Te3Cl2, aus der isotypen Reihe Te2X (X Cl, Br, J) von Te2Br und Te2J, sowie von β- und α-TeJ wurden dargestellt und zur Strukturbestimmung nach Einkristallmethoden verwendet. Te3Cl2 kristallisiert monoklin, Raumgruppe P21/n, z = 4, mit a = 10,136(15), b = 8,635(3), c = 7,039(8) A und β = 100,74(6)°. Die Struktur besteht aus makromolekularen Bauelementen von Telluratomen, deren Beziehung zur Struktur des elementaren Tellurs behandelt wird. Te2X kristallisiert orthorhombisch, Raumgruppe Pnam, z = 8. Gitterkonstanten fur das Bromid [Jodid] sind: a=14,921(12) [15,295(3)], b=12,843(6) [13,694(4)], c=4,005(3) [4,123(2)] A. Die Struktur besteht aus unendlichen Doppelketten, die zu Bandern von Te6-Ringen mit Bootkonformation kondensiert sind, und verbruckenden Halogenatomen an den Randern. β-TeJ kristallisiert monoklin, Raumgruppe C2/m, z = 8, mit Gitterkonstanten a = 15,383(2), b = 4,182(2), c = 11,999(2) A und β = 128,09(1)°. Die Struktur besteht aus unendlichen Ketten von Telluratomen, an welchen die Jodatome alternierend verbruckende und terminale Positionen besetzen. α-TeJ kristallisiert triklin, Raumgruppe P1, z = 8, mit Gitterkonstanten a = 9,958(3), b = 7,992(2), c = 8,212(4) A, α = 104,37(11), β = 90,13(4) und γ = 102,89(7)°. Der makromolekulare Bauzusammenhang der Subhalogenide des Tellurs ist im α-TeJ zu einem Te4-Ring (dem Te4J4-Molekul) entartet. Die untersuchten Strukturen werden vergleichend und im Zusammenhang mit Strukturen anderer Tellurverbindungen diskutiert. On the Subhalides of Tellurium Crystals of Te3Cl2, within the isotypic series Te2X (X Cl, Br. I) of Te2Br and Te2I, as well as of β-TeI and α-TeI have been prepared and were used for structure determination with single crystal methods. Te3Cl2 is monoclinic, space group P21/n, z = 4, with a = 10.136(15), b = 8.635(3), c = 7.039(8) A and β = 100.74(6)°. The structure consists of macromolecular units of tellurium atoms, which relation to the structure of elemental tellurium is discussed. Te2X is orthorhombic with space group Pnam. z = 8. Lattic parameters for the bromide [iodide] are: a = 14.921(12) [15.295(3)], b = l2.843(6)[13.694(4)], c = 4.005(3)[4.123(2)] A. The structure consists of infinite double chains condensed to ribbons of Te6 rings with boat conformation and bridging halogen atoms at the edges. β-TeI is monoclinic, space group C2/m, z = 8, with cell constants a = 15.383(2), b = 4.182(2), c = 11.999(2) A and β = 128.09(1)°. The structure consists of endless chains of tellurium atoms along which the iodine atoms occupy alternating bridging and terminal positions. α-TeI is triclinic. space group P1, z = 8, with lattice parameters a = 9.958(3), b = 7.992(2), c = 8.212(4) A α = 104.37(11), β = 90.13(4) and γ = 102.89(7)°. The macromolecular building principle of the subhalides of tellurium is degenerated in α-TeI to a Te4-ring (the Te4I4 molecule). The structures studied are compared to each other and discussed in connection with structures of other tellurium compounds.

Lithium nitride is a solid electrolyte with a high Li + -conductivity at ambient temperatures and attractive properties for an application in a primary battery. The proposed presence of a polarizable ion N 3- in the unique hexagonal structure could be proved by measurements of Czochralski-grown single crystals applying the methods of modern solid state science, particular X-ray diffraction. A model for the conduction mechanism of the Li + -ions is presented. Using crystal-chemical considerations a material for application at higher temperatures could be found among the lithium-nitride-halides.

A simple technique to prepare highly oriented superconducting YBaCuO ceramics is presented. The same technique has also been found to work in Bi-Sr-Ca-Cu-O system. The slightly BaO-deficient material obtained is more durable in humid environment as compared to the conventional ceramics. An additional improvement of durability is achieved by surface modification. Finally, two independent analytical methods are described for determining the redox state (O nonstoichiometry) precisely.

X-ray investigations on single crystals of the series of rare-earth compounds Na5RESi4O12 with RE as Sc or Y were carried out at room temperature and 300°C. They show a dependence of the inner symmetry of the main conductive channels on the type of the RE ion. A simple analysis of the conductivity mechanism is presented.

Single crystals of H3PW12O40·28H2O, H3PW12O40·21H2O and H4SiW12O40·28H2O have been prepared. The proton diffusion coefficients and conductivities have been determined for the pure protonic as for partially deuterated samples. The numbers are found to be lower than reported in the literature, the Nernst-Einstein relationship is fulfilled and there is almost no isotopic effect. The results indicate the vehicle-mechanism as the operating proton conduction mechanism instead of the Grotthuss mechanism as frequently suggested.

Protonic conduction in zeolites is optimized. The approach is based on a vehicle-mechanism for the transport process. The parameters controlling protonic conduction are discussed. Fully hydrated “NH4-zeolite A” has a room temperature conductivity of 2×10 −3 Ω −1 cm −1 . The material was successfully used in oxygen concentration cells (e.g. MnO2/NH4-zeolite A/Zn).

One-dimensional bulk proton conduction parallel to the c axis was observed in solid lithium hydrazinium sulfate, LiN 2 H 5 SO 4 . The conductivity in this direction is 2 × 10 −8 ω −1 cm −1 at 25°C and shows an activation enthalpy of 0.75 ± 0.07 eV. The two-dimensional conductors HUO 2 AsO 4 ·4H 2 O and HUO 2 PO 4 ·4H 2 O were studied as a function of their water content. The conductivities are 8 × 10 −6 and 3 × 10 −5 ω −1 cm −1 in the orthorhombic phase at −10°C, with activation enthalpies of 0.70 ± 0.05 and 0.57 ± 0.07 eV, respectively. Indications of peritectic transitions to the tetragonal phases were observed in the temperature ranges 15 to 47 and −5 to 10°C, respectively. The transition depends on the water content which appears to control the increase in conductivity in this material. The dependence upon various sample parameters is discussed. Fast proton transport in solids is proposed to occur by a “vehicle mechanism”, i.e. the motion of N 2 H + 5 , H 3 O + - or other proton-containing groups.

The lithium nitride halides are fast, solid lithium ion conductors. Their potential use in practical battery type applications is discussed with emphasis on the kinetic, thermodynamic, and structural properties of lithium nitride chloride, Li 9 N 2 Cl 3 . The general requirements of high decomposition voltage, absence of metallic dendrite formation during charge and discharge, low electronic transference number, and stability against reaction with lithium are fulfilled, in addition to fast ion transport and easy preparation and handling. The application of thin film solid electrolytes, e.g. , in integrated circuits, is proposed.

A galvanic cell is presented to measure equilibrium iodine partial pressures in the Te-I system. The cell arrangement allows the determination of rather low vapour pressures. The cell performance at higher iodine pressures was verified by measuring the e.m.f. of the formation reaction of AgI from the elements in the temperature range from 300 to 420 K, which is above the melting point of iodine. γ-AgI rather than β-AgI was the solid electrolyte used in these investigations. An attempt was made to estimate the lower limit of measurable iodine activities.

Crystals of PtCl 3 are obtained from the vapour phase in closed fused silica ampoules at temperatures near 785 K and at a chlorine pressure of about 26 atm. The thermodynamic parameters characterizing the single-phase field of solid PtCl 3 are determined. The growth of the crystals results from vapour transport which is a combination of a sublimation and two dissociative reactions. The complex transport is investigated using the solubility theory of Schafer. The theory reveals an increase in the transport rate with increasing chlorine pressure when the source is heated to the temperature which separates the fields of solid PtCl 2 and PtCl 3 .

A solid state electrochemical technique was employed to study the dissociation oxygen partial pressures of DyFeO 3 and Dy 3 Fe 5 O 12 at elevated temperatures. The standard enthalpies ΔH o f and entropies ΔS o f of formation were obtained to be - 1349.7 kJ/mol and - 253.2 J/mol·K for DyFeO 3 in the temperature range from 1173 to 1473 K, and - 4879.5 kJ/mol and - 1011.6 J/mol·K for Dy 3 Fe 5 O 12 in the temperature range from 1173 to 1523 K, respectively.

The proton conductivity and lattice constants of H 3 OUO 2 AsO 4 .3H 2 O (HUAs) have been detemined at pressures up to 7 GPa. A drop of the preexponential factor and the activation enthalpy of the conductivity and of the crystallographic C lattice parameter at 2.5 GPa is interpreted as a transition from the vehicle mechanism of proton transport at low pressure to the GROTTHUSS mechanism at high pressure.

The crystal structure of CuISe3 has been determined. CuISe3 is a rhombohedral crystal with space group R 3 m and lattice parameters a = 1407.9(6) pm, c = 1418.7(2) pm (hexagonal setting). The structure consists of six-membered Se-rings in chain-type configuration, which are surrounded by rhombs of Cu2I2-units oriented parallel to the c-direction and alternating in height. A comparison with the crystal structure of CuBrSe3 is given.

The crystal structure of Li 3 N was determined using single crystals obtained from the reaction of N 2 with liquid lithium. The proposed structure of Zintl and Brauer could be confirmed. Li 3 N is hexagonal: a = 3.648(1) A , c = 3.875(1) A , Z = 1. The space group was determined to be p 6/ mmm . The structure was refined, with anisotropic temperature factors, to R = 0.025 and R ( w ) = 0.026.

The title systems include a large number of intermediate phases which have been characterized by their phase relations on the respective quasibinary sections and by their crystal structures. Oxygen and nitrogen sites of the solvent molecules act as donors to the central lithium ions which, thereby, mainly get a tetrahedral coordination; halogen ions may also contribute to this first coordination sphere. A structural concept is developed on the basis of the tendency of condensation of the lithium coordination-polyhedra by sharing common vertices. The highest ionic conductivity is observed for compounds with discrete complex ions which are formed by the smaller solvent molecules.

Die Phasendiagramme der Systeme LiFLiH und LiFLiOH wurden durch DTA-, Rontgen- und Leitfahigkeits-Untersuchungen aufgeklart. LiF und LiH bilden eine Mischkristallreihe mit einem Minimum bei 630°C (65 Mol.-% LiH). Unterhalb 550°C entsteht eine Mischungslucke (bei Raumtemperatur: 60–90 Mol.-% LiH). Das System LiFLiOH weist ein Eutektikum bei 432°C (85 Mol.-% LiOH) auf. Die Ionenleitfahigkeiten beider Systeme andern sich im ein- wie auch zweiphasigen Bereich monoton steigend mit dem Gehalt an LiH bzw. LiOH. Das Zweiphasen-Gebiet LiFLiOH zeigt das typische Leitfahigkeitsverhalten der jeweils dominierenden Phase. Eine drastische Leitfahigkeitserhohung in den zweiphasigen Bereichen wird nicht beobachtet. Fur Anwendungen konnen die im Gebiet fester Losungen sich mit dem Mischungsverhaltnis reziprok zueinander verandernde thermodynamische Stabilitat und Ionenleitfahigkeit nach Bedarf optimal eingestellt werden. Die Versuchsanordnung fur die Wechselstrom-Impedanzmessung wird beschrieben. Phase Equilibria and Ionic Transport Properties of the Systems LiFLiH and LiFLiOH The phase diagrams of the systems LiFLiH and LiFLiOH were determined by DTA, X-ray and ac-impedance measurements. Solid solutions of LiF and LiH exist with a minimum point at 630°C (65 Mol.-% LiH). A miscibility gap appears below 550°C (60–90 Mol.-% LiH at room temperature). The system LiFLiOH shows an eutectic point at 432°C (85 Mol.-% LiOH). The ionic conductivities increase both in single- and two phase regions monotonically with increasing amounts of LiH or LiOH, respectively. The conductivity pattern of the predominantly present phase is observed in the case of the two phase system LiFLiOH. A large increase of the conductivity in any of the 2-phase mixtures is not observed. Optimal conditions in the thermodynamic stability and ionic conductivity may be chosen in the regions of solid solutions depending on the specific application. The experimental arrangement for ac impedance measurements is described.

In this paper the subiodide of tellurium, α-TeI, is presented as a new ionic conductor. Electromotive-force measurements on solid state galvanic cells of the types Ag/AgI/TeI, Te; Ag/AgI/TeI, TeI4; TeI, Te/AgI/TeI, TeI4; TeI, Te/TeI/TeI, TeI4 are given. The temperature dependence of cells e.m.f. is presented. Comparison of the e.m.f. data with the total acconductivity measurements leads to the conclusion that α-TeI has a remarkable partial iodine ionic conductivity.