The homogeneity ranges, order-disorder transition, and structures of the nonstoichiometric monosulfides of zirconium

Kim, S.-J.; Nguyễn, Thu Hà; Franzen, Hugo F.

doi:10.1016/0022-4596(87)90181-2

Cited by 14 publications

(7 citation statements)

References 8 publications

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“…The effusion method has been found to be useful in the controlled preparation of novel refractory phases at high temperatures, typically 1500 K or above.15 In particular, the method has been used to prepare nonstoichiometric vanadium monosulfide,16 which exhibits a continuous symmetry breaking transition,17 and more recently a similar study with a similar result was carried out for defect zirconium monosulfide. 18 In addition, the new stoichiometric materials TmgSn19 and TmisSza20 and the very nearly stoichiometric Ys-^Se?21 and Lua+A22 were prepared by Knudsen vaporization. The preparation of these new materials depended fundamentally upon the very close control of change of stoichiometry afforded by the Knudsen effusion method.…”

Section: Effusion Methodsmentioning

confidence: 99%

Condensed-Phase Transitions in Binary Systems During Dynamic Vaporization Experiments: Effusion and Transpiration

Edwards¹,

Franzen²

1995

J. Phys. Chem.

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Section: Effusion Methodsmentioning

confidence: 99%

Condensed-Phase Transitions in Binary Systems During Dynamic Vaporization Experiments: Effusion and Transpiration

Edwards¹,

Franzen²

1995

J. Phys. Chem.

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“…Exceptions hereto are TiS [11], ZrS [12] and HfS [13], where film methods were used. As there exist reports on nonstoichiometry and a homo geneity range for compounds adopting this structure type, e. g. ZrS [14], we found it worthwhile to deter mine the crystal structure of ZrTe (WC), especially with respect to a possible partial occupation of atom positions.…”

mentioning

confidence: 99%

The Crystal Structure of WC Type ZrTe. Advantages in Chemical Bonding as Contrasted to NiAs Type ZrTe

Örlygsson¹,

Harbrecht²

1999

Zeitschrift Für Naturforschung B

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Single crystals of WC type ZrTe were prepared from the elements. A single crystal structure determination of this structure type was performed for the first time: ZrTe (WC) crystallizes in the hexagonal space group P6m2 (No. 187), hP2, Z -1, a -377.06(5), c = 386.05(8) pm; 84 reflections, 5 variables, R(F) = 0.037. The distinctions in bonding for ZrTe (WC) and a hypothetical stoichiometric ZrTe crystallizing in the NiAs type structure were analyzed on the basis of extended Hiickel calculations. Heteronuclear interactions contribute most strongly to the stability of both structures. Attractive Zr-Zr interactions energetically favour ZrTe (WC) relative to ZrTe (NiAs). The Fermi level of ZrTe (WC) resides in a local minimum of the DOS, whereas that of ZrTe (NiAs) intersects a local DOS maximum, and is pushed up by about 0.5 eV, expressing the decisive destabilization of NiAs type ZrTe. As a consequence, metal deficiency is observed for ZrTe (NiAs), in contrast to ZrTe (WC).Recent investigations of the Zr-Te system have brought to light several new compounds, among them two metal-rich phases Zr?Te [ 1 ] and Z nT e [2], ZrsTeö [3], adopting a NiAs type-related structure, and Z n 3oTe2 [4], In the course of an extensive study of the system, a phase adopting the WC type struc ture awoke our interest. A WC type zirconium tel luride was first reported by Hahn and Ness [5], with a range of homogeneity assigned to it. The existence of the phase was confirmed later on [6 -8 ], however, with an equiatomic composition, practically exclud ing a homogeneity range. DTA measurements indi cated a decomposition of ZrTe (WC) at 1505 K into ZrsTe4 [6 , 9] and a phase richer in tellurium [8]. In every case the phase was identified by its lattice pa rameters as determined by powder X-ray diffraction means. To our knowledge [10], a complete single crystal diffraction study of a compound crystalliz ing in the WC type structure has not appeared in the literature. Exceptions hereto are TiS [11], ZrS [12] and HfS [13], where film methods were used. As there exist reports on nonstoichiometry and a homo geneity range for compounds adopting this structure type, e. g. ZrS [14], we found it worthwhile to deter mine the crystal structure of ZrTe (WC), especially with respect to a possible partial occupation of atom positions.A remarkable feature of ZrTe is its apparent di morphism, with high and low temperature modifi cations crystallizing in the NiAs and WC type struc tures, respectively. However, for the high tempera ture phase, metal deficiency is observed [7,8 ]. In an attempt to gain some understanding of this phe nomenon, extended Hiickel calculations were car ried out. Similar calculations dealing with the NaCl-WC type dimorphism have been performed [15,16], Apart from ZrTe, NiAs-WC type dimorphism has been reported for NbS, NbN and TiS [10], Crystals of ZrTe were synthesized from a mixture of the elements (Te: 99.999%, Fluka; Zr: 99.8%, ChemPur, nzr : nxe = 1 : 1) in a sealed, argonfilled tantalum tube, which in turn was contained in an e...

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“…The ternary metal-rich sulfides and phosphides discovered and investigated in this work could not be prepared using transport techniques but crystals of other compounds were obtained through transport methods during this research. The use of I2 as a transport agent, a temperature gradient of 100 °C from the center to the side of the tube furnace, and a maximum temperature of 1050 °C resulted in the formation of beautifully shaped crystals of two known phases, yellow octahedral crystals of ZrOS [68] and maroon crystals of rhombohedral Zr^.^S [3,5]. Inhomogeneous, polyphasic materials (particles of metal surrounded by polysulfide or polyphosphide coatings) formed with the tube furnace technique caused problems when used for arcmelting.…”

Section: Low Temperature Tube Furnace Techniques (< 1100 K )mentioning

confidence: 99%

“…Na^O in the anti-fluorite structure can reasonably be considered "ionic" and even though Na/0 = 2, there is no significant metal-metal bonding in this structure and NagO is not a metal-rich compound by the criteria used here. Zr^.^S [3,4], on the other hand, is found in two different superstructures of the "rocksalt" structure type with the ratio Zr/S < 1. The rhombohedral structure of Zr^.^S is well characterized [3,5] and is a metal-rich compound because it exhibits metallic behavior and important metal-metal interactions.…”

Section: General Introductionmentioning

confidence: 98%

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Studies of high temperature ternary phases in mixed-metal-rich early transition metal sulfide and phosphide systems

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The homogeneity ranges, order-disorder transition, and structures of the nonstoichiometric monosulfides of zirconium

Cited by 14 publications

References 8 publications

Condensed-Phase Transitions in Binary Systems During Dynamic Vaporization Experiments: Effusion and Transpiration

Condensed-Phase Transitions in Binary Systems During Dynamic Vaporization Experiments: Effusion and Transpiration

The Crystal Structure of WC Type ZrTe. Advantages in Chemical Bonding as Contrasted to NiAs Type ZrTe

Studies of high temperature ternary phases in mixed-metal-rich early transition metal sulfide and phosphide systems

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