A simple gas introduction system for cryogenic powder X-ray diffraction

Hodyss, Robert; Vu, Tuan; Choukroun, Mathieu; Cable, Morgan L.

doi:10.1107/s1600576721006671

Cited by 2 publications

(4 citation statements)

References 10 publications

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“…The sample was prepared as follows: approximately 1 bar of gaseous 1,3-butadiene was deposited into a Tedlar sample bag (SKC Ltd.) at room temperature. The gas bag was then connected to a 0.3 mm borosilicate capillary via a custom-built apparatus for gas handling described elsewhere . The capillary tube, which had been prealigned and rotated on the goniometer head, was then purged with butadiene gas for several minutes prior to being flash-frozen to 85 K by an Oxford Cryostream 800 (temperature control to within ±1 K).…”

Section: Experimental Methodsmentioning

confidence: 99%

“…The gas bag was then connected to a 0.3 mm borosilicate capillary via a custom-built apparatus for gas handling described elsewhere. 20 The capillary tube, which had been prealigned and rotated on the goniometer head, was then purged with butadiene gas for several minutes prior to being flash-frozen to 85 K by an Oxford Cryostream 800 (temperature control to within ±1 K). Following condensation of sufficient amounts of solid butadiene to give adequate diffraction signals, the capillary was immediately flame-sealed to isolate the sample from the atmosphere.…”

Section: ■ Introductionmentioning

confidence: 99%

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1,3-Butadiene on Titan: Crystal Structure, Thermal Expansivity, and Raman Signatures

Maynard-Casely

Cable

et al. 2022

ACS Earth Space Chem.

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Titan is one of the most Earth-like objects in the Solar System, hosting a nitrogen-rich atmosphere and an impressive inventory of organics ranging from simple to complex. 1,3-Butadiene has been suggested to be one of the photochemical products that could be present on Titan's surface. As the simplest conjugated hydrocarbon, it is expected to partake in many chemical processes that influence Titan's geology and evolution. However, the crystal structure and thermal expansivity of 1,3-butadiene, two of its most fundamental properties, have remained largely unknown for over eight decades, especially at cryogenic conditions often encountered on planetary bodies. In this work, a series of powder X-ray diffraction and micro-Raman experiments have been conducted in order to elucidate the crystal structure and thermal behavior of solid 1,3-butadiene between 85 and 165 K. Specifically, a single crystalline phase (space group P2 1 /c) is observed in the temperature range of study in which the butadiene molecules form layers of zigzag chains that are stabilized by an intricate network of intermolecular C−H•••π interactions. This monoclinic structure is shown to exhibit significant anisotropic thermal expansion along the three directions with the majority occurring along the crystallographic b-axis. The calculated bulk density of 1,3-butadiene (0.877 g/cm 3 at 150 K) is considerably lower than previously realized. These results help enhance our understanding of the putative molecular solids that make up Titan's surface and could hold important implications for physical as well as mechanical processes occurring on this icy satellite.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

1,3-Butadiene on Titan: Crystal Structure, Thermal Expansivity, and Raman Signatures

Maynard-Casely

Cable

et al. 2022

ACS Earth Space Chem.

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“…The open end of the capillary was attached to a custom-built system for introducing gases (in this case, acetylene) into the capillary, which allows for precise manipulation and deposition of the analyte gas. 39 The system is comprised of two valves and a flowmeter which are connected to an 8 cm long polyamide-coated silica capillary tube (360 μm outside diameter, 100 μm inside diameter) through a standard 1/8″ Swagelok elbow, which is mounted to a manual XYZ micromanipulator. 39 The silica capillary was slowly directed inside of the borosilicate capillary to prepare for acetylene deposition.…”

Section: Experimental Techniquesmentioning

confidence: 99%

“… 39 The system is comprised of two valves and a flowmeter which are connected to an 8 cm long polyamide-coated silica capillary tube (360 μm outside diameter, 100 μm inside diameter) through a standard 1/8″ Swagelok elbow, which is mounted to a manual XYZ micromanipulator. 39 The silica capillary was slowly directed inside of the borosilicate capillary to prepare for acetylene deposition. Following the nitrogen purge, the acetylene gas flow into liquid pyridine was initiated at room temperature; the sample temperature was gradually lowered in ∼10 K increments using a liquid nitrogen-cooled Oxford Cryosystems Cryostream 800 (temperature control to within ±1 K) until the mixed sample solidified at ∼186 K. For ethane wetting (mixing) experiments, the sample was cooled to 110 K after the co-crystal was verified to form within the capillary at 180 K. A 1 L Tedlar gas sample bag was filled with gaseous ethane, which was subsequently condensed through the custom-built gas introduction system and into the capillary so the liquid ethane could mix with the pyridine:acetylene co-crystal sample.…”

Section: Experimental Techniquesmentioning

confidence: 99%

Experimental Characterization of the Pyridine:Acetylene Co-crystal and Implications for Titan’s Surface

Czaplinski

Cable

et al. 2023

ACS Earth Space Chem.

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Titan, Saturn's largest moon, has a plethora of organic compounds in the atmosphere and on the surface that interact with each other. Cryominerals such as co-crystals may influence the geologic processes and chemical composition of Titan's surface, which in turn informs our understanding of how Titan may have evolved, how the surface is continuing to change, and the extent of Titan's habitability. Previous works have shown that a pyridine:acetylene (1:1) co-crystal forms under specific temperatures and experimental conditions; however, this has not yet been demonstrated under Titan-relevant conditions. Our work here demonstrates that the pyridine:acetylene co-crystal is stable from 90 K, Titan's average surface temperature, up to 180 K under an atmosphere of N 2 . In particular, the co-crystal forms via liquid− solid interactions within minutes upon mixing of the constituents at 150 K, as evidenced by distinct, new Raman bands and band shifts. X-ray diffraction (XRD) results indicate moderate anisotropic thermal expansion (about 0.5−1.1%) along the three principal axes between 90−150 K. Additionally, the co-crystal is detectable after being exposed to liquid ethane, implying stability in a residual ethane "wetting" scenario on Titan. These results suggest that the pyridine:acetylene co-crystal could form in specific geologic contexts on Titan that allow for warm environments in which liquid pyridine could persist, and as such, this cryomineral may preserve the evidence of impact, cryovolcanism, or subsurface transport in surface materials.

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A simple gas introduction system for cryogenic powder X-ray diffraction

Cited by 2 publications

References 10 publications

1,3-Butadiene on Titan: Crystal Structure, Thermal Expansivity, and Raman Signatures

1,3-Butadiene on Titan: Crystal Structure, Thermal Expansivity, and Raman Signatures

Experimental Characterization of the Pyridine:Acetylene Co-crystal and Implications for Titan’s Surface

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