The Jahn-Teller effect in K2PbCu(NO2)6

“…In particular, K 2 PbCu(NO 2 ) 6 undergoes two successive structural transitions at 281 and 273 K which were previously investigated using electron paramagnetic resonance (EPR) techniques . On the basis of precise X-ray and neutron measurements, Noda et al found that the K 2 PbCu(NO 2 ) 6 elpasolite phase transitions proceed from the face centered cubic phase 1 to the tetragonal phase 2 at 281 K with the c -axis shortened, and to phase 3 with a symmetry lower than orthorhombic, due to the cooperative Jahn–Teller effect …”

Section: Introductionmentioning

confidence: 99%

Gel Growth of K₂PbCu(NO₂)₆-Elpasolite Single Crystals

Dong

Besara

Henderson

et al. 2017

Crystal Growth & Design

View full text Add to dashboard Cite

Single crystals of K 2 PbCu(NO 2 ) 6 have been grown from aqueous solution; however, convection effects often introduce defects in the crystals and contribute to a high nucleation rate. Here, we show that K 2 PbCu(NO 2 ) 6 single crystals can be grown in silica gels where convection is largely eliminated, resulting in diffusion controlled crystal growth. The diffusion coefficients of the Cu 2+ -and Pb 2+ -acetates in potassium silica gel were determined using a classical onedimensional (1D) diffusion model. The influence of the reactant concentrations on the nucleation location and growth was investigated. The growth rate was analyzed using Frank's model for diffusion-controlled growth rates for a radially symmetric crystal. The magnetic susceptibility of K 2 PbCu(NO 2 ) 6 shows evidence of 1D antiferromagnetic behavior based on a Bonner− Fisher fit.

show abstract

“…Crystal Structure of the Usual R2Pb[Cu(N02)6 J Type ComplexesAs for the structure o f the lowest tem p eratu re phase o f K 2P b [C u (N 0 2)6], H arrow field et al[7,8] assum ed a ferrodistortive o rd er in w hich all the [ C u ( N 0 2)6]4~ o ctah ed ra are tetragonally com pressed along [001] axis. O n th e o th er hand, R einen et al [ 9 -1 1 ] proposed an altern ativ e m odel from their ESR results w hich have been explained by an an ti ferrodistortive ord ered system consisting o f tw o crystallographically n o n eq u iv alen t [C u (N 0 2)6]4_ octa h ed ra elongated along [ 100] and [010] crystal axes.…”

mentioning

confidence: 99%

An ESR Study of Structural Phase Transitions of(NH₄)₂Pb[Cu(NO₂)₆]

Asaji

Prabhumirashi

Nakamura

1986

Zeitschrift Für Naturforschung A

View full text Add to dashboard Cite

The structural changes o f (N H 4) 2P b [C u (N 0 2)6] crystals during the phase transitions at 316, 287, and 95 K were studied by means o f a single crystal ESR technique. Anisotropic g values [9 > 9±) were obtained in the lowest temperature phase IV, whereas the ESR spectra recorded in the intermediate phases III and II, in which the crystal is known to be tetragonally compressed along the c axis, could be interpreted by use o f effective g values [g ( c) < g (_L c)]. In the highest temperature phase I an isotropic g value was obtained. The phases I, II, and III o f the present complex can be assumed to be very similar to the corresponding phases observed above ~ 250 K for the com pounds R2P b [C u (N 0 2) 6] with R = K, Rb, Cs, and Tl. However, the lowest temperature phase transition transforms the phase III with an antiferrodistortive order o f the elongated [C u (N 0 2)6]4_ octahedra into the phase IV with a ferrodistortive one. This occurs only for the complex with R = N H 4 and is very unusual. The results o f the 14N N Q R experiments already reported for the phases III and IV could be well explained by the present newly proposed model.

show abstract

The Jahn-Teller effect in K₂PbCu(NO₂)₆

Cited by 36 publications

References 22 publications

Potassium barium hexanitrocuprate(II) at 295 K

Potassium barium hexanitrocuprate(II) at 295 K

Gel Growth of K₂PbCu(NO₂)₆-Elpasolite Single Crystals

An ESR Study of Structural Phase Transitions of(NH₄)₂Pb[Cu(NO₂)₆]

Contact Info

Product

Resources

About

The Jahn-Teller effect in K2PbCu(NO2)6

Cited by 36 publications

References 22 publications

Potassium barium hexanitrocuprate(II) at 295 K

Potassium barium hexanitrocuprate(II) at 295 K

Gel Growth of K2PbCu(NO2)6-Elpasolite Single Crystals

An ESR Study of Structural Phase Transitions of(NH4)2Pb[Cu(NO2)6]

Contact Info

Product

Resources

About

The Jahn-Teller effect in K₂PbCu(NO₂)₆

Gel Growth of K₂PbCu(NO₂)₆-Elpasolite Single Crystals

An ESR Study of Structural Phase Transitions of(NH₄)₂Pb[Cu(NO₂)₆]