Journal Article

PUBDB-2025-01218

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Compression of [121]Tetramantane to over 50 GPa - Phase transformations and elastic properties

Heimes, H. (Corresponding author)Extern* ; Wierbik, J.Extern* ; Bradby, J.Extern*EMBL*

2025
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.diamond.2025.112087  doi:10.3204/PUBDB-2025-01218

Abstract: The hydrocarbon [121]tetramantane (C$_{22}$H$_{28}$) is a promising precursor material for the high-pressure high-temperature synthesis of nanodiamonds due its diamond-like carbon bonding network. We present a comprehensive study of its structural behaviour under pressure using single-crystal and synchrotron X-ray diffraction, Raman spectroscopy, and density functional theory calculations. At ambient conditions, [121]tetramantane crystallises in monoclinic space group ${P2_1/n}$ with lattice parameters of a = 7.7192(1) Å, b = 8.0112(1) Å, c = 12.8281(2) Å, = 104.635(2)°, =2, and a density of 1.265(3) g/cm$^3$. Under non-hydrostatic diamond anvil cell compression, we observe two phase transitions: first to a phase with space group $P2/n$ at 1 GPa, followed by a transition to a high-pressure phase above 8 GPa indexed to a unit cell with space group $P2/m$ and lattice parameters a = 14.62(1) Å, b = 7.78(1) Å, c = 6.39(1) Å, = 94.4(2)°, and =3, and a density of 2.010(3)${g/cm^3}$ at 31 GPa. The isothermal bulk modulus ${B_0}$ increases significantly from the value of the ambient phase of (19.4 ± 0.9) GPa to that of the high-pressure phase of (147.5 ± 1.7) GPa. Upon recovery, [121]tetramantane transforms back to a $P2/n$ phase with similar lattice parameters compared to the initial ${P2_1/n}$ structure, but possesses significantly different relative peak intensities. This study provides valuable insights on the structure-property relationships of [121]tetramantane and suggests an optimal pressure of 8 GPa for the use of [121]tetramantane as a precursor for nanodiamond synthesis.

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Contributing Institute(s):

1. FS DOOR-User (FS DOOR-User)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. FS-Proposal: I-20230434 (I-20230434) (I-20230434)
3. FS-Proposal: I-20240136 (I-20240136) (I-20240136)

Experiment(s):

1. PETRA Beamline P02.2 (PETRA III)

Appears in the scientific report 2025

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