Anisotropic thermal expansion of the acetylene–ammonia co-crystal under Titan's conditions

2020 ◽  
Vol 53 (6) ◽  
pp. 1524-1530
Author(s):  
Tuan H. Vu ◽  
Helen E. Maynard-Casely ◽  
Morgan L. Cable ◽  
Robert Hodyss ◽  
Mathieu Choukroun ◽  
...  

Acetylene and ammonia are known to form a stable orthorhombic co-crystal under the surface conditions of Saturn's moon Titan (1.5 bar = 150 kPa, 94 K). Such a material represents a potential new class of organic minerals that could play an important role in Titan's geology. In this work, the thermal expansion of this co-crystalline system has been derived from in situ powder X-ray diffraction data obtained between 85 and 120 K. The results indicate significant anisotropy, with the majority of the expansion occurring along the c axis (∼2% over the temperature range of interest). Rietveld refinements reveal little change to the structure compared with that previously reported by Boese, Bläser & Jansen [J. Am. Chem. Soc. (2009), 131, 2104–2106]. The expansion is consistent with the alignment of C—H...N interactions along the chains in the a and b axes, and weak intermolecular bonding in the structural layers along the c axis.

2010 ◽  
Vol 504 ◽  
pp. S155-S158 ◽  
Author(s):  
J. Bednarcik ◽  
C. Curfs ◽  
M. Sikorski ◽  
H. Franz ◽  
J.Z. Jiang

2015 ◽  
Vol 628 ◽  
pp. 102-106 ◽  
Author(s):  
Konstantin D. Litasov ◽  
Sergey V. Rashchenko ◽  
Alexander N. Shmakov ◽  
Yury N. Palyanov ◽  
Alexander G. Sokol

2009 ◽  
Vol 24 (12) ◽  
pp. 3551-3558 ◽  
Author(s):  
S.J. Patwe ◽  
S. Nagabhusan Achary ◽  
Avesh K. Tyagi

Ca0.5Th0.5VO4 was prepared by a solid-state reaction of component oxides and characterized by powder x-ray diffraction (XRD) at ambient and higher temperatures and impedance spectroscopy. Crystal structure was refined by Rietveld refinements from powder XRD data. At room temperature, Ca0.5Th0.5VO4 has a zircon-type tetragonal (I41/amd) lattice with unit cell parameters: a = 7.2650(1) and c = 6.4460(1) Å. Despite the large charge difference, Ca2+ and Th4+ are statistically distributed over a single site. The crystal structure of Ca0.5Th0.5VO4 is built from the (Ca/Th)O8 (bisdisphenoid) and VO4 tetrahedra. The in situ high-temperature XRD studies on Ca0.5Th0.5VO4 revealed anisotropic thermal expansion behavior with coefficients of thermal expansion αc = 10.96 × 10−6/°C and αa = 5.32 × 10−6/°C. The impedance measurements carried out in the temperature range from ambient to 800 °C indicate semiconducting behavior with appreciable ionic conductivity above 400 °C. The activation energy obtained from the temperature-dependent AC conductivity data is ∼1.37 eV. In wider range of frequencies and temperatures, the relative permittivity of approximately 50 to 60 is observed for Ca0.5Th0.5VO4.


2010 ◽  
Author(s):  
J. Bednarcik ◽  
M. Miglierini ◽  
C. Curfs ◽  
H. Franz ◽  
Jirí Tucek ◽  
...  

2009 ◽  
Vol 113 (22) ◽  
pp. 9568-9572 ◽  
Author(s):  
Wen Fei Zhou ◽  
Guang Tao Fei ◽  
Xin Feng Li ◽  
Shao Hui Xu ◽  
Li Chen ◽  
...  

2017 ◽  
Vol 254 (5) ◽  
pp. 1600695 ◽  
Author(s):  
I. N. Leontyev ◽  
A. A. Kulbakov ◽  
M. Allix ◽  
A. Rakhmatullin ◽  
A. B. Kuriganova ◽  
...  

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