New compounds A2−xV8O16 (A = K,Tl) with hollandite type structure

Abriel, W.; Rau, F.; Range, K.‐J.

doi:10.1016/0025-5408(79)90090-4

Cited by 47 publications

(23 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(1) Rogers (1993); (2) Range & Zintl (1983); (3) Longo & Kierkegaard (1970); (4) Evans & Mrose (1955); (5) Abriel et al (1979); (6) Abraham & Mentre (1994); (7) Kanke et al (1995); (8) ; (9) Evans & Mrose (1960). (Fig.…”

Section: Q-ud Structuresmentioning

confidence: 99%

Structural chemistry of vanadium oxides with open frameworks

Zavalij

Whittingham

1999

Acta Crystallogr B Struct Sci

329

264

View full text Add to dashboard Cite

The present work is dedicated to a crystal-chemical and topographical analysis of vanadium oxides with open structures. The review covers, apart from a few exceptions, only pure vanadium oxide structures with vanadium in oxidation states greater than +3. Purely tetrahedral frameworks are not discussed because of their traditional, well known crystal chemistry and only a few examples of cluster compounds are provided. Structural classi®cation and notation of vanadium oxide frameworks are proposed based on the following scheme: polyhedra 3 chain 3 layer 3 three-dimensional framework. Thus, approximately 60 types of vanadium oxide frameworks are divided into ®ve classes by type of coordination polyhedra present and into 14 subclasses by a more complex structural formation. Details are also given of the analysis of vanadium± oxygen coordination polyhedra and their metamorphosis: tetrahedron±trigonal bipyramid±square pyramid±octahedron, as well as the combinatorial deduction of possible structures for the most common framework types.

show abstract

Section: Q-ud Structuresmentioning

confidence: 99%

Structural chemistry of vanadium oxides with open frameworks

Zavalij

Whittingham

1999

Acta Crystallogr B Struct Sci

329

264

View full text Add to dashboard Cite

show abstract

“…The structure symmetry is given by I 4/m, and the V atoms share a crystallographically identical 8h site. 2 Therefore, the good metallic behavior is well explained by the mixed-valence state of vanadium atoms: V 3.75+ , V 3+ (3d 2 )/V 4+ (3d 1 ) = 1/3. This charge degree of freedom possibly plays a key role in the observed complex MIT.…”

Section: Introductionmentioning

confidence: 96%

Electromagnetic properties of hollandite K2V8O16under pressure

et al. 2011

View full text Add to dashboard Cite

The magnetic susceptibility and resistivity of V 4+ /V 3+ mixed-valence vanadium oxide (hollandite K 2 V 8 O 16 ) were measured under pressure. The resistivity measurements show that the charge-order transition temperature (T CO ) is suppressed with increasing pressure up to 1 GPa, as observed in many kinds of charge-ordering compounds. At 1 GPa, the pressure dependence of T CO suddenly changes its tendency; further compression of the system above 1 GPa leads T CO to higher temperatures. This clearly shows an appearance of a new ground state at around 1 GPa. This situation is also revealed by dc-susceptibility measurements: The nonmagnetic ambient ground state suddenly turns into a magnetic state at around 1 GPa. These high-pressure experimental results could be explained as a switching between two kinds of orbital-charge-spin ordered structures.

show abstract

“…11 We assume various d electron distributions on the V ions and compare the Madelung energies where we use the room-temperature crystal structure reported for K 2 V 8 O 16 . 12 We first calculate the Madelung energy for the system with a hypothetical uniform electron distribution, where all the V ions are assumed to have the valence state of V 3.75+ ; we find the energy of −3341.386 eV/sc where sc is the unit cell of the observed √ 2a× √ 2a×2c superlattice. We then calculate the Madelung energies for various CO patterns with V 3+ or V 4+ and find that a number of CO patterns are more stable than the energy for the uniform electron distribution.…”

Section: A Madelung Energy and Co Patternsmentioning

confidence: 99%

Theoretical study of the electronic states of hollandite vanadateK2V8O16

2008

View full text Add to dashboard Cite

We consider electronic properties of hollandite vanadate K2V8O16, a one-dimensional zigzag-chain system of t2g orbitals in a mixed valent state. We first calculate the Madelung energy and obtain the relative stability of several charge-ordering patterns to determine the most stable one that is consistent with the observed superlattice structure. We then develop the strong-coupling perturbation theory to derive the effective spin-orbit Hamiltonian, starting from the triply-degenerate t2g orbitals in the VO6 octahedral structure. We apply an exact-diagonalization technique on small clusters of this Hamiltonian and obtain the orbital-ordering pattern and spin structures in the ground state. We thereby discuss the electronic and magnetic properties of K2V8O16 including predictions on the outcome of future experimental studies.

show abstract

New compounds A2−xV8O16 (A = K,Tl) with hollandite type structure

Cited by 47 publications

References 17 publications

Structural chemistry of vanadium oxides with open frameworks

Structural chemistry of vanadium oxides with open frameworks

Electromagnetic properties of hollandite K2V8O16under pressure

Theoretical study of the electronic states of hollandite vanadateK2V8O16

Contact Info

Product

Resources

About