Unexpectedly stable nitrogen, oxygen, carbon monoxide and argon clathrate hydrates from vapour-deposited amorphous solid water: an X-ray and two-step differential scanning calorimetry study

1990 ◽  
Vol 86 (22) ◽  
pp. 3785 ◽  
Author(s):  
Andreas Hallbrucker ◽  
Erwin Mayer
Keyword(s):  
Differential Scanning Calorimetry ◽  
Carbon Monoxide ◽  
Amorphous Solid ◽  
Clathrate Hydrates ◽  
Scanning Calorimetry ◽  
Differential Scanning Calorimetry Study ◽  
Amorphous Solid Water ◽  
X Ray ◽  
Solid Water

scholarly journals A simultaneous X-ray diffraction–differential scanning calorimetry study into the phase transitions of mefenamic acid

2019 ◽  
Vol 52 (6) ◽  
pp. 1264-1270 ◽  
Author(s):  
Yuying Pang ◽  
Asma Buanz ◽  
Richard Telford ◽  
Oxana V. Magdysyuk ◽  
Simon Gaisford ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Mefenamic Acid ◽  
Cell Expansion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Differential Scanning Calorimetry Study ◽  
Polymorphic Transitions ◽  
X Ray ◽  
New Form ◽  
The Stability

In this study, the polymorphic transitions of mefenamic acid (MA) were studied by synchrotron X-ray powder diffraction combined with differential scanning calorimetry (XRD-DSC). The initial material was found to be phase-pure form I which, when heated, produces two endotherms that can be observed by DSC at 162.72 and 219.55°C. The former was found to correspond to a solid–solid enantiotropic transition from form I to a mixture of forms II and III. The latter is the melting point of form II. As form I is heated, significantly greater unit-cell expansion is seen in the a direction than in b and c, which can be explained by the stronger intermolecular interactions in the bc plane. Refinements of the reported MA structures against the patterns collected during heating revealed that at 175°C there exists a mixture of forms I, II and III, whereas only forms II and III remain at 205°C. However, reflections are observed at both temperatures which cannot be fitted with the known forms of MA. It is hypothesized that a new form of MA is produced upon heating. The stability of MA after the enantiotropic transition temperature is II > III > I, which differs from the previously reported II > I > III.

Amorphous Solid Water: An X-ray Diffraction Study

Science ◽  
1974 ◽  
Vol 186 (4167) ◽  
pp. 927-928 ◽  
Author(s):  
C. G. Venkatesh ◽  
S. A. Rice ◽  
A. H. Narten
Keyword(s):  
Diffraction Study ◽  
Amorphous Solid ◽  
X Ray Diffraction ◽  
Amorphous Solid Water ◽  
X Ray ◽  
Solid Water

scholarly journals The Effective Surface Area of Amorphous Solid Water Measured by the Infrared Absorption of Carbon Monoxide

2019 ◽  
Vol 878 (2) ◽  
pp. 94 ◽  
Author(s):  
Jiao He ◽  
Aspen R. Clements ◽  
SM Emtiaz ◽  
Francis Toriello ◽  
Robin T. Garrod ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Surface Area ◽  
Infrared Absorption ◽  
Amorphous Solid ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Amorphous Solid Water ◽  
Solid Water
Sign in / Sign up

Export Citation Format

Share Document