Les structures type PbFCl (EOI) et type anti-Fe2As (C38) des composés ternaires à deux anions MXY

Flahaut, Jean

doi:10.1016/0022-4596(74)90063-2

Cited by 65 publications

(36 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…ZrAs 0.90(1) (Se 0.50(1) As 0.50 ) = ZrAs 1.40 Se 0.50 crystallizes in the UPS branch (substitution variant of the Fe 2 As type, often referred to as ZrSiS type) of the PbFCl type structure characterized by a larger ratio c/a ≥ 2.0 together with a large fractional parameter of the metal atom (Zr) z ≥ 2.2 as compared to the BiOI type [17]. In this structure type typically the larger anions occupy the 2c site and the smaller anions the 2a site.…”

Section: Crystal Structure and Chemical Compositionmentioning

confidence: 99%

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs_1.4Se_0.5

Schmidt

Cichorek

Niewa

et al. 2005

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Abstract.Single crystals of ZrAs 1.4 Se 0.5 (PbFCl type structure) were grown by chemical vapour transport. While their thermodynamic and transport properties are typical for ordinary metals, the electrical resistivity exhibits a shallow minimum at low temperatures. Application of strong magnetic fields does not influence this anomaly. The minimum of the resistivity in ZrAs 1.4 Se 0.5 apparently originates from interaction between the conduction electrons and structural twolevel systems. Significant disorder in the As-Se substructure is inferred from X-ray diffraction and electron microprobe studies.

show abstract

Section: Crystal Structure and Chemical Compositionmentioning

confidence: 99%

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs_1.4Se_0.5

Schmidt

Cichorek

Niewa

et al. 2005

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…1) -contains compounds with mainly ionic interactions, whereas another -coined as anti-Fe2As type -is encountered with compounds showing strongly covalent character, e.g. UPS (Flahaut, 1974;Johnson & Jeitschko, 1973). ' 0108-7681/83/040401-04501.50 We have emphasized that, within its field of existence, the PbFC1 type itself shows marked variations with respect to crystal geometry and even bonding.…”

Section: Introduetlonmentioning

confidence: 95%

Influence of high hydrostatic pressure on the crystal structure of BaFCl in the pressure range up to 6.5 GPa

Beck¹,

Limmer²,

Denner³

et al. 1983

Acta Crystallogr Sect B

View full text Add to dashboard Cite

High-pressure X-ray diffraction measurements were made with BaFC1 single crystals (space group P4/nmm) using a diamond-anvil cell on a four-circle diffractometer (six data sets, 30 to 50 reflections, R values ranging from 2.5 to 5.0%). This compound does not show a pressure-induced phase transition up to 6.5 GPa at ambient temperatures. At lower pressures the compressibility of the c axis is larger than that of the a axis. At 2 GPa the compressibility becomes isotropic and at higher pressures again anisotropic, but now with an increasing c/a ratio. Such effects of pressure and the changes in positional parameters are discussed in comparison with the known structural data for a whole series of PbFCl-type compounds. Changes in the ion 'size' are accompanied by distortions of the structural framework leading to a more efficient packing. While the Madelung number decreases during this process, the relative loss of ionic lattice energy is compensated for by an increase in interactions due to polarization, which can be traced by the movement of the Ba 2+ ions within their coordination sphere. IntroduetlonIt is remarkable that mixed-anion compounds MFX with larger cations M mostly crystallize with the same structural arrangement regardless of the large differences in size and polarizability of the atoms found in such compounds. It has been stated that this variety in constituents leads to different 'branches' of the structure type, of which one -the PbFC1 type ( Fig. 1) -contains compounds with mainly ionic interactions, whereas another -coined as anti-Fe2As type -is encountered with compounds showing strongly covalent character, e.g. UPS (Flahaut, 1974;Johnson & Jeitschko, 1973). ' 0108-7681/83/040401-04501.50 We have emphasized that, within its field of existence, the PbFC1 type itself shows marked variations with respect to crystal geometry and even bonding. The structural differences within this arrangement, ranging from a coordination lattice (found with MOC1, MFCI and MHC1 compounds) to a layer structure (MOI, MFI, MHI), have been discussed by B~irnighausen, Brauer & Schultz (1965).A detailed analysis of well refined structures of fluorohalides (Beck, 1979) has shown an interesting correlation between positional parameters and the polarizability of the constituent ions. In the course of these studies it was our aim to trace the changes in bonding type induced by higher pressures by the same minute analysis of structural details.High-pressure X-ray investigations using powder specimens of fluorochlorides and -bromides of Eu, Sin, Pb and alkaline earths have shown no structural rearrangement up to pressures between 5 and 10 GPa (1 GPa = 10 kbar) (Beck, 1978a). The lattice constants of these compounds decrease linearly with pressure except for BaFC1, which was therefore chosen for further studies under high pressure using single crystals. © 1983 International Union of Crystallography INFLUENCE OF HYDROSTATIC PRESSURE ON THE STRUCTURE OF BaFC1Experimental BaFC1 crystals were prepared by sintering of the bin...

show abstract

“…Mössbauer spectroscopy has shown that ionic bond is present in SnCl 2 . This is probably the reason for the single Sn 2+ line of figure 5b 1 . The weaker SnCl bonds, compared to Sn-F bonds, are the reason for the very weak lattice (extremely weak line intensity at ambient temperature).…”

Section: (B)mentioning

confidence: 99%

“…1), making it an anisotropic structure, in contrast with the isotropic cubic structure of BaF 2 ( fig. 1) [1]. The Ba 2+ ions are bonded to four fluoride ions at the corners of a square, like half of its cubic coordination in BaF 2 .…”

Section: Introductionmentioning

confidence: 99%

Study of double ionic disorder (cationic and anionic) and disorder of two kinds of tin(II) (ionic and covalent) within the same material: the incredibly complex Ba_1-xSn_xCl_1+yF_1-y solid solution and its study by Mössbauer spectroscopy

Boufas¹,

Dénès²,

Kochuparampil³

et al. 2006

WIT Transactions on the Built Environment, Vol 85

View full text Add to dashboard Cite

A doubly disordered Ba 1-x Sn x Cl 1+y F 1-y solid solution has been prepared. X-ray diffraction shows that Ba and Sn are fully disordered on the Ba site of the BaClF structure. In addition, while the two anionic sites remain ordered, for y>0 the y Cl in excess are disordered with the remaining (1-y) F on the F site, whereas for y<0, the (-y) excess F are disordered with the remaining (1+y) Cl on the Cl site. 119 Sn Mössbauer spectroscopy showed the Ba 1-x Sn x Cl 1+y F 1-y solid solution is a truly unique material. Indeed, in addition to the rarity of being a doubly disordered solid solution over a wide range of chemical composition, it also exhibits a variable mixture of ionic tin(II) (Sn 2+ stannous ions, with a non-stereoactive lone pair) and covalently bonded tin(II) (with a stereoactive lone pair). A new material, Ba 2 SnCl 6 , has been prepared and its crystal structure solved. It contains octahedrally coordinated Sn 2+ , with a perfectly non-stereoactive lone pair, for the first time in a chloride. This makes the lone pair a potential charge carrier.

show abstract

Les structures type PbFCl (EOI) et type anti-Fe2As (C38) des composés ternaires à deux anions MXY

Cited by 65 publications

References 12 publications

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs_1.4Se_0.5

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs_1.4Se_0.5

Influence of high hydrostatic pressure on the crystal structure of BaFCl in the pressure range up to 6.5 GPa

Study of double ionic disorder (cationic and anionic) and disorder of two kinds of tin(II) (ionic and covalent) within the same material: the incredibly complex Ba_1-xSn_xCl_1+yF_1-y solid solution and its study by Mössbauer spectroscopy

Contact Info

Product

Resources

About

Les structures type PbFCl (EOI) et type anti-Fe2As (C38) des composés ternaires à deux anions MXY

Cited by 65 publications

References 12 publications

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs1.4Se0.5

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs1.4Se0.5

Influence of high hydrostatic pressure on the crystal structure of BaFCl in the pressure range up to 6.5 GPa

Study of double ionic disorder (cationic and anionic) and disorder of two kinds of tin(II) (ionic and covalent) within the same material: the incredibly complex Ba1-xSnxCl1+yF1-y solid solution and its study by Mössbauer spectroscopy

Contact Info

Product

Resources

About

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs_1.4Se_0.5

Crystallographic disorder and electron scattering on structural two-level systems in ZrAs_1.4Se_0.5

Study of double ionic disorder (cationic and anionic) and disorder of two kinds of tin(II) (ionic and covalent) within the same material: the incredibly complex Ba_1-xSn_xCl_1+yF_1-y solid solution and its study by Mössbauer spectroscopy