7790-48-9Relevant articles and documents
Vapor pressure and thermodynamic functions of TeI4 and its decomposition products
Kut'in,Polyakov,Churbanov,Snopatin
, p. 1018 - 1023 (2007)
Using a flow method, we have measured the vapor pressure of tellurium tetraiodide, an attractive reagent for chemical vapor deposition technology. The results, combined with earlier tensimetric data, have been used to evaluate the basic thermodynamic functions of TeI4 and its thermolysis products.
An investigation of the Tl–Te–I system and crystal structure of the Tl5Te2I
Babanly, Dunya M.,Aliev, Ziya S.,Imamaliyeva, Samira Z.,Zú?iga, Fco. Javier,Madariaga, Gotzon,Tagiyev, Dilqam B.
, p. 997 - 1005 (2016)
The phase relations in the Tl–Te–I system have been experimentally investigated over the entire concentration range mainly by thermal analysis (DTA), X-ray diffraction (XRD) applied to equilibrated alloys. The isothermal section at 300?K, liquidus surface projection and the phase diagrams of the six isopleth sections have been constructed. The homogeneity ranges and primary crystallization fields for the all phases, as well as, the character and temperature of non- and monovariant equilibria were determined in the system. The crystal structure of the Tl5Te2I compound has been determined by single crystal X-Ray diffraction. It is found to be stoichiometric and isostructural which crystallize in the In5Bi3structure type with four formula units in the tetragonal system, space group I4/mcm, а?=?9.001(2); c?=?13.291(4) ?.
Synthesis and structure of Re4(μ3-Te)4(TeBr2) 4Br8
Schulz Lang,Abram,Stra?hle
, p. 251 - 253 (1996)
Re4(μ3-Te)4(TeBr2) 4Br8 is obtained from the elements at 550°C in an evacuated glass ampoule. The diamagnetic compound forms air-stable, metallic lustre black crystals crystallizing in the tetragonal space group 14 with a = 1120.2(2), c = 1393.5(3) pm, and Z = 2. The crystal structure is built up by isolated cluster molecules Re4(μ3-Te)4(TeBr2) 4Br8 occupying the centres 4 at 1/2, 1/2, 0 and 0, 0, 1/2. The inner sceleton is formed by a Re4Te4 heterocubane unit with short Re-Re distances of 277 and 283 pm, which can be discussed as single bonds. Each Re atom coordinates in addition two Br- ligands and one TeBr2 molecule. For Re therefore results the oxidation state +IV. Reaction of Re4(μ3-Te)4(TeBr2) 4Br8 with I2 yields (TeI4)4. ? Johann Ambrosius Barth 1996.
Stabilization of decatellurium molecules in isolated and concatenated clusters
Guenther, Anja,Isaeva, Anna,Ruck, Michael
, p. 254 - 260 (2013/04/10)
Black, shiny crystals of the molecular cluster compounds (Te 10)[M(TeX4)(TeX3)]2 (M/X = Rh/Cl (1), Ir/Br (2)), (Te10)[Ru(TeI4)(TeI2)] 2 (3), (Te10)[M(TeI4)(TeI2)] 2(TeI4)(Te2I2) (M = Rh (4), Ir (5)) as well as the one-dimensional cluster polymer (Te10I 2)[Ir(TeI4)]2(Te4)I2 (6) were synthesized by melting reactions of an electron-rich transition metal M (M = Ru, Rh, Ir) with tellurium and TeX4 (X = Cl, Br, I). X-ray diffraction on single-crystals revealed that the compounds crystallize in the triclinic space group type P1. 4 and 5 show [3+1]-dimensional modulations of their structures. All compounds contain binuclear complexes with central μ-η4:η4-bridging Te10 units and terminal halogenidotellurate(II) groups. Each of the transition metal cations is in a slightly distorted octahedral coordination by six tellurium atoms; the two [MTe6] octahedra share a common edge. With the tellurium atoms acting as electron-pair donors, the 18 electron rule is fulfilled for the electrophilic M atoms. The central tricyclo[5.1.1.13, 5]- decatellurium molecule consists of two ecliptically stacked Te4 rings, which are linked through two tellurium atoms. The symmetric or asymmetric 3c4e bonds along these almost linear bridges are in analogy to polyanionic forms of tellurium, while the tricyclic conformation is stabilized by the strong bonding to the transition-metal cations. Multi-center bonding (3c4e) is also present in the terminal square [Te+IIX4]2- and the T-shaped [Te+IIX3]- groups. The crystal structures of 4 and 5 are organized in layers of (Te10)[M(TeI 4)(TeI2)]2n+ clusters (n ≤ 2) that are quite robust upon oxidation or reduction as shown by molecular calculations. These clusters alternate with incommensurately modulated layers that probably consist of TeI42- anions and a previously unknown Te2I2 molecule. The uncertainty arises primarily from equal scattering powers of I and Te atoms as well as from the known flexibility of the electron count of the Te10 unit. In 6, neutral Te4 rings concatenate (Te10I2)[Ir(TeI 4)]2 clusters into chains, which run parallel to the a axis. Copyright
Hexatellurium rings in coordination polymers and molecular clusters: Synthesis and crystal structures of [M(Te6)]X3 (M = Rh, Ir; X = Cl, Br, I) and [Ru2(Te6)](TeBr3) 4(TeBr2)2
Guenther, Anja,Ruck, Michael
, p. 317 - 323 (2012/05/20)
The reaction of an electron-rich transition metal M (M = Ru, Rh, Ir), tellurium and TeX4 (X = Cl, Br, I) resulted in black crystals of five ternary coordination polymers with the general composition [M III(Te6)]X3 (M = Rh, Ir) and of the molecular cluster compound [RuII2(Te6)](Te IIBr3)4(TeIIBr2) 2. X-ray diffraction on single-crystals revealed that the compounds [M(Te6)]X3 crystallize isostructurally in the trigonal space group type Rβar{3}χ. In their crystal structures linear, positively charged [MIII(Te6)] chains form the motif of a hexagonal rod packing. In the chain, each of the formally uncharged Te 6 molecules with chair conformation acts as a bis-tridentate bridging ligand to two M atoms. The octahedrally coordinated M atoms are spiro atoms in the chain of trans vertices sharing heterocubane fragments. Including the isolated halide ions, which provide charge balance, the entire arrangement resembles a cut-out of the α-polonium structure type.In the monoclinic compound Ru2Te12Br16 (space group P2 1/n), the ruthenium atoms of the hetero-cubane core of the molecular cluster [Ru2(Te6)](TeBr3)4(TeBr 2)2 are saturated by terminal bromidotellurate(II) groups. Again, the Te6 ring is formally uncharged. With the tellurium atoms acting as electron-pair donors the 18 electron rule is fulfilled for the M atoms in all compounds. Copyright
Phase diagram and thermodynamic properties of the system As-Te-I
Aliev,Babanly,Babanly,Shevelkov,Amiraslanov
, p. 602 - 608 (2011/02/23)
The As-Te-I system has been investigated primarily by means of DTA, XRD analyses and EMF measurements with an arsenic electrode. The T-x diagram of the binary As-I system was accurately redefined and its phase diagram was constructed. A projection of the liquidus surface, an isothermal section at 300 K, and a series of polythermal sections of the phase diagram were constructed. The previously reported ternary compounds As5Te7I, As 4Te5I2 and As8Te7I 5 were confirmed to be equilibrium phases; the positions of phase areas with their participation were established. Areas of primary crystallization of phases, types and coordinates of the invariant equilibria on the T-x-y diagram were determined. From the X-ray powder diffraction (XRD) analysis, the crystallographic parameters of As4Te5I 2 and As8Te7I5 were determined. From the EMF measurements, the partial molar functions of arsenic (ΔG?,ΔH?,ΔS?) as well as standard integral thermodynamic functions of ternary compounds were calculated.
Phase equilibriums and thermodynamic properties of the system Bi-Te-I
Babanly,Tedenac,Aliyev,Balitsky
, p. 349 - 353 (2009/12/08)
The system Bi-Te-I was studied by methods of differential thermal analysis and the X-ray diffraction, and also by measurements of electromotive forces (EMF) of concentration chains of type(-) Bi (s) | liquid electrolytic conductor, Bi3+ | (Bi-T
Synthesis, structure, and properties of the tantalum-rich suicide chalcogenides Ta15Si2QxTe10-x (Q = S, Se)
Debus, Stephan,Harbrecht, Bernd
, p. 431 - 438 (2008/10/08)
The quaternary tantalum suicide chalcogenides Ta15Si2QxTe10-x (Q = S, Se) are accessible from proper, compacted mixtures of the respective dichalcogenides, silicon and elemental tantalum at 1770 K in sealed molybdenum tubes. The structures were determined from the strongest X-ray intensities of fibrous crystals with cross sections of about 3 μm and confirmed by fitting the profile of single phase X-ray diffractograms. The phases Ta15Si2S3.5Te6.5 and Ta15Si2. Se3.5Te6.5 crystallize in the monoclinic space group C2/m with two formula units per unit cell, a = 2393.7(1) pm, b = 350.08(2) pm, c = 1601.2(1) pm, β = 124.700(4)°, and a = 2461.3(2) pm, b = 351.70(2) pm, c= 1601.7(1) pm, β = 124.363(5)°, respectively. Tri-capped trigonal prismatic Ta9Si clusters stabilized by encapsulated Si atoms can be seen as the characteristic unit of the structure. The clusters are fused into twin columns which are connected by additional Ta atoms, thus forming corrugated layers. The remaining valences at the surfaces of the layered Ta-Si substructure are saturated by those of chalcogen atoms which are coordinated only from one side by three, four or five Ta atoms. Few bridging covalent Ta-S-Ta and Ta-Se-Ta bonds and, otherwise, dispersive interactions between the Q atoms hold these nearly one nanometer wide slabs together. The phases are moderate metallic conductors. There is no evidence for any electronic instability within 10-310 K in spite of the high anisotropy of the structures. Wiley-VCH Verlag GmbH, 2001.
Ta11Si2Se8 - Condensed tetrakaidecahedral Ta9Si clusters arranged to an open network structure
Mrotzek, Antje,Harbrecht, Bernd
, p. 87 - 93 (2007/10/03)
Ta11Si2Se8 was synthesized from a pre-reacted mixture of the elements in a sealed tantalum tube at 1570 K. Mo-doped crystals were obtained in a welded molybdenum crucible by a chemical transport reaction using TeI4 as a transport agent. The structure of Mo0.11Ta(10.89(2))Si2Se8 has been determined by single crystal X-ray means [Pnnm, Z = 2, a = 1184.4(1) pm, b = 1939.4(1) pm, c = 346.48(2) pm, wR2 = 0.069]. The structure of the ternary phase was verified by means of a rietveld profile fit of a powder X- ray diffractogram. The silicide is isotypic with Ta11Ni2Se8. The structure is composed of Si-centred, tricapped trigonal prismatic Ta9Si cluster. The tetrakaidecahedral Ta9Si clusters are fused into twin chains by sharing the Ta(pr) atoms of facing triangulated prism faces and one out of three capping atoms Ta(c). Intercluster linkage of the remaining Ta(c) atoms generates a microporous (∞)/3[SiTa2(c) Ta(1/2)(c) Ta(6/2)(pr)] substructure. The channels of the metal network are sheathed by three-, four- , five-, and sixfold coordinated Se atoms. Four-probe dc resistivity measurements revealed the Mo-doped phase to be a moderate metallic conductor. The bonding interactions contributing to the stability of Ta11Si2Se8 and distinctions in bonding for Ta11Si2Se8 and Ta11Ni2Se8 are analyzed on the basis of semi-empirical extended Huckel calculations.
Polymorphism of Tellurium(IV) Iodide
Kniep, Ruediger,Beister, Heinz Juergen,Wald, Dieter
, p. 966 - 980 (2007/10/02)
Idiomorphous crystals of five different polymorphic modifications (α-ε) of TeI4 are simultaneously grown from solutions of TeI4 and concentrated HI in methanol by evaporating the solvent at room temperature. δ-TeI4 is the only stable phase at normal conditions.Phase transformations of α-, β-, γ- and ε-TeI4 to the final stage δ-TeI4 take place by heating and run through discrete intermediates.The observed graduations lead to a sequence γ-, β-, α-, ε-TeI4 which indicates increasing metastability .The crystal structures of α-TeI4 (trigonal; Pml; a = 4.228(2), c = 6.684(6) Angstroem, Z = 0.5; Dx = 5.10 g/cm3), β-TeI4 (orthorhombic; Pn21m; a = 6.888(2), b = 14.539(3), c = 16.753(4) Angstroem, Z = 8; Dx = 5.03 g/cm3) and γ-TeI4 (monoclinic; P21/c; a = 11.199(4), b = 13.599(4), c = 22.158(6) Angstroem, β = 98.10(3) deg, Z = 16; Dx = 5.05 g/cm3) are related to the known crystal structure of δ-TeI4. α-TeI4 ( Te0.5I2 ) is an isotype of the 2H-CdI2 structure with random distribution of Te over the Cd-positions.The crystal structures of β-, γ- and δ-TeI4 contain discrete tetrameric molecules (TeI4)2(TeI3(+)I(-))2 which are generated by ordered distributions of Te over 1/4 of the octahedral holes of a 2H- (β) and 4H-sequence (γ, δ) of the nearly close packed iodine layers.A nearly cubic close packing of Iodine atoms is observed in the crystal structure of ε-TeI4 (tetragonal; I41/amd; a = 16.875(6), c = 11.829(5) Angstroem, Z = 16; Dx = 5.01 g/cm3).The ordered distribution of Te in 1/4 of the octahedral holes leads to tetrameric molecules (TeI3(+)I(-))4 in a cubanelike arrangement which, thus far, has been observed only in the crystal structures of TeCl4 and TeBr4.The Madelung Parts of Lattice Energies, MAPLE, of β-, γ-, δ- and ε-TeI4 are calculated. - Keywords: Polymorphism, Crystal Structures, Binary Compounds, Tellurium(IV) Iodide
