Reversible phase transition in laser-shocked 3Y-TZP ceramics observed via nanosecond time-resolved x-ray diffraction

Octahedral tris(ethylenediamine) coordination complexes demonstrate helicoidal chirality, due to the arrangement of the ligands around the metal core. The enantiomers of the nitrate salts [Ni(en)3](NO3)2 and [Zn(en)3](NO3)2 spontaneously resolve to form a mixture of conglomerate crystals, which present a reversible phase transition from space group P6322 to enantiomorphic P6522 or P6122, with the latter depending on the handedness of the enantiomer. We report here the synthesis and characterization of [Mn(en)3](NO3)2 and [Co(en)3](NO3)2, which are isostructural to the Zn(II) and Ni(II) derivatives. The Mn(II) analogue undergoes the same phase transition centered at 150(2) K, as determined by single-crystal X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry. The Co(II) derivative does not demonstrate a phase transition down to 2 K, as evidenced by powder X-ray diffraction and heat capacity measurements. The phase transition does not impact the magnetic properties of the Ni(II) and Mn(II) analogues; these high spin compounds display Curie behavior that is consistent with S = 1 and 5/2, respectively, down to 20 K, while the temperature-dependent magnetic moment for the Co(II) compound reveals a significant orbital contribution.

Download Full-text

Die quaternären Systeme ZnAl2S4-ZnGa2S4, ZnAl2S4-CdAl2S4 und ZnAl2S4-ZnAl2Se4. Röntgenographische und schwingungsspektroskopisehe Untersuchungen / Investigation of the Quaternary Systems ZnAl2S4-ZnGa2S4, ZnAl2S4-CdAl2S4 and ZnAl2S4-ZnAl2Se4 by X-Ray Diffraction and Vibrational Spectroscopy

Zeitschrift für Naturforschung B ◽

10.1515/znb-1983-0306 ◽

1983 ◽

Vol 38 (3) ◽

pp. 311-316 ◽

Cited By ~ 12

Author(s):

H. Haeuseler ◽

A. Cansiz

Keyword(s):

Phase Transition ◽

Vibrational Spectroscopy ◽

Solid Solutions ◽

Homogeneity Range ◽

Binary Systems ◽

X Ray Diffraction ◽

X Ray ◽

Reversible Phase Transition ◽

Reversible Phase ◽

Fir Spectra

The quasi-binary systems Zn1-xCdxAl2S4, ZnAl2(1-x)Ga2xS4 and ZnAl2S4(1-x)Se4x have been investigated by X-ray diffraction and vibrational spectroscopy. In the spinel ZnAI2S4 up to 20% of Zn can be replaced by Cd. In the two other systems, ZnAl2S4 has no detectable homogeneity range. The thiogallate phases have much broader ranges of homogeneity. The compositions of the compounds at the phase boundary of the thiogallate phase are Zn0.4Cd0.6Al2S4, ZnGa0.4Al1.6S4, and ZnAl2S2.8Se1.2. At approximately 950 °C ZnAl2Se4 undergoes a reversible phase transition to a wurtzite-type structure. This phase transition is also observed for the solid solutions ZnAl2S4(1-x)Se4x; with 1.0 > x > 0.3. The FIR spectra are discussed.

Download Full-text

A Reversible Phase Transition of 2D Coordination Layers by B–H∙∙∙Cu(II) Interactions in a Coordination Polymer

Molecules ◽

10.3390/molecules24173204 ◽

2019 ◽

Vol 24 (17) ◽

pp. 3204 ◽

Cited By ~ 3

Author(s):

Lei Gan ◽

Pol G. Fonquernie ◽

Mark E. Light ◽

Gantulga Norjmaa ◽

Gregori Ujaque ◽

...

Keyword(s):

Phase Transition ◽

Coordination Polymer ◽

Thermal Activation ◽

Bet Surface Area ◽

Co2 Uptake ◽

X Ray Diffraction ◽

X Ray ◽

Reversible Phase Transition ◽

Open Metal Sites ◽

Reversible Phase

Materials that combine flexibility and open metal sites are crucial for myriad applications. In this article, we report a 2D coordination polymer (CP) assembled from CuII ions and a flexible meta-carborane-based linker [Cu2(L1)2(Solv)2]•xSolv (1-DMA, 1-DMF, and 1-MeOH; L1: 1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane). 1-DMF undergoes an unusual example of reversible phase transition on solvent treatment (i.e., MeOH and CH2Cl2). Solvent exchange, followed by thermal activation provided a new porous phase that exhibits an estimated Brunauer-Emmett-Teller (BET) surface area of 301 m2 g−1 and is capable of a CO2 uptake of 41 cm3 g−1. The transformation is reversible and 1-DMF is reformed on addition of DMF to the porous phase. We provide evidence for the reversible process being the result of the formation/cleavage of weak but attractive B–H∙∙∙Cu interactions by a combination of single-crystal (SCXRD), powder (PXRD) X-ray diffraction, Raman spectroscopy, and DFT calculations.

Download Full-text

Phase Transition of Na3As under Pressure

Zeitschrift für Naturforschung B ◽

10.1515/znb-1990-1007 ◽

1990 ◽

Vol 45 (10) ◽

pp. 1388-1392 ◽

Cited By ~ 6

Author(s):

Heinz Jürgen Beister ◽

Karl Syassen ◽

Jürgen Klein

Keyword(s):

Phase Transition ◽

High Pressure ◽

Structural Properties ◽

Pressure Range ◽

Structure Type ◽

X Ray Diffraction ◽

X Ray ◽

Equation Of States ◽

Reversible Phase Transition ◽

Reversible Phase

We have investigated the high pressure behaviour of Na3As by powder X-ray diffraction. At 3.6 GPa the material undergoes a reversible phase transition from the Na3As structure (P 63/mmc, a = 487.4(8) pm, c = 851.5(20) pm, Z = 2, at 3.6 GPa) to the Li3Bi structure type (Fm 3̅ m, a = 683.5(15) pm, Z = 4, at 3.6 GaP). The equation of states is given for the pressure range up to 26 GPa. Results are discussed with respect to structural properties of related A3IBV-compounds

Download Full-text