On the polymorphism of benzocaine; a low-temperature structural phase transition for form (II)

2009 ◽  
Vol 65 (4) ◽  
pp. 509-515 ◽  
Author(s):  
Eric J. Chan ◽  
A. David Rae ◽  
T. Richard Welberry
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Structural Phase Transition ◽  
Room Temperature ◽  
Structural Phase ◽  
Space Group ◽  
Polymorphic Forms ◽  
Similar Phase

A low-temperature structural phase transition has been observed for form (II) of benzocaine (BZC). Lowering the temperature doubles the b-axis repeat and changes the space group from P212121 to P1121 with γ now 99.37 °. The structure is twinned, the twin rule corresponding to a 21 screw rotation parallel to a. The phase transition is associated with a sequential displacement parallel to a of zigzag bi-layers of ribbons perpendicular to b*. No similar phase transition was observed for form (I) and this was attributed to the different packing symmetries of the two room-temperature polymorphic forms.

Phase Transitions and Water Dynamics of [Mn(H2O)6](ClO4 )2 Studied by Differential Scanning Calorimetry and Neutron Scattering Methods

2000 ◽  
Vol 55 (9-10) ◽  
pp. 759-764 ◽  
Author(s):  
E. Mikuli ◽  
A. Migdał-Mikuli ◽  
I. Natkaniec ◽  
J. Mayer
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Neutron Scattering ◽  
Structural Phase Transition ◽  
Room Temperature ◽  
Structural Phase ◽  
Water Dynamics ◽  
Water Molecules ◽  
Temperature Phase ◽  
Solid Phases

Abstract DSC measurements performed at 95 -290 K have shown that [Mn(H 2 O) 6 ](CIO 4) 2 possesses, besides a high-temperature phase, existing above 323 K, four low-temperature solid phases. The inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) pat-terns registered at 20 -290 K have supported the DSC results and provided evidence that the investigated substance possesses even more than five solid phases. The IINS spectra have shown that in the room-temperature phase, water molecules perform fast stochastic reorientation at the picosecond scale. The orientational disorder characteristic for the room-temperature phase can be easily overcooled and frozen. Even by relatively slow cooling at ca. 40 K/hour a metastable, orientational (protonic) glass phase is formed below ca. 160 K. Below ca. 100 K, a structural phase transition was observed by the NPD, however the IINS spectra indicate existence of the pure ordered low-temperature phase only after annealing the sample for a few hours at 100 K. On heating, a structural phase transition takes place at ca. 120 K, and at ca. 225 K water molecules begin fast reorientation.

Temperature-induced reversible structural phase transition of 1,4-dimethyl-1,4-diazabicyclo[2.2.2]octane bis(perchlorate)

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 55914-55919 ◽  
Author(s):  
Li-Zhuang Chen ◽  
Xing-Xing Cao ◽  
Deng-Deng Huang ◽  
Qi-Jian Pan
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Phase Change ◽  
Phase Change Material ◽  
Structural Phase Transition ◽  
Room Temperature ◽  
Paraelectric Phase ◽  
Structural Phase ◽  
Disorder Transition ◽  
Change Material

A novel molecular-based phase change material was synthesized. The phase transition from a room temperature to a low temperature paraelectric phase might be driven by the order–disorder transition of ClO4− anions and the ordering of twisting motions of the dabco ring.

Low-Temperature Structure (T = 235 K) and Structural Phase Transition in [(C2H5)4N]2SnCl6

1987 ◽  
Vol 103 (1) ◽  
pp. 73-78 ◽  
Author(s):  
H. Ketata ◽  
M. H. Ben Ghozlen ◽  
A. Daoud ◽  
I. Pabst
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Temperature Structure

Structural phase transition at low temperature in La2−x Sr x CuO4 aroundx=0.12 under magnetic fields

1996 ◽  
Vol 46 (S3) ◽  
pp. 1237-1238 ◽  
Author(s):  
Takao Suzuki ◽  
Kaichiro Chiba ◽  
Takayuki Goto ◽  
Tetsuo Fukase
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Magnetic Fields ◽  
Structural Phase Transition ◽  
Structural Phase

Effects of partial substitution on Tc and low-temperature structural phase transition in La2−xBaxCuO4

1991 ◽  
Vol 185-189 ◽  
pp. 791-792 ◽  
Author(s):  
Yoji Koike ◽  
Tsutomu Kawaguchi ◽  
Syoichi Hosoya ◽  
Naoki Watanabe ◽  
Takahashi Noji ◽  
...  
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Partial Substitution

Low temperature frustrated structural phase transition in single crystal La1.85Sr0.15CuO4

1995 ◽  
Vol 197 (5-6) ◽  
pp. 439-443 ◽  
Author(s):  
Z.J. Yang ◽  
M. Yewondwossen ◽  
R.A. Dunlap ◽  
D.J.W. Geldart ◽  
S.L. Yuan ◽  
...  
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Single Crystal ◽  
Structural Phase Transition ◽  
Structural Phase

scholarly journals Near-room-temperature reversible giant barocaloric effects in [(CH3)4N]Mn[N3]3 hybrid perovskite

2020 ◽  
Vol 1 (9) ◽  
pp. 3167-3170 ◽  
Author(s):  
Jorge Salgado-Beceiro ◽  
Ariel Nonato ◽  
Rosivaldo Xavier Silva ◽  
Alberto García-Fernández ◽  
Manuel Sánchez-Andújar ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Room Temperature ◽  
Structural Phase ◽  
Inorganic Perovskite ◽  
First Order ◽  
Hybrid Perovskite

We report giant reversible barocaloric effects in [(CH3)4N]Mn[N3]3 hybrid organic–inorganic perovskite, near its first-order cubic-monoclinic structural phase transition at T0 ∼ 305 K.

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