Synthesis and Compressibility of Novel Nickel Carbide at Pressures of Earths Outer Core

• We report the high-pressure synthesis and the equation of state (EOS) of a novel nickel carbide (Ni3C). It was synthesized in a diamond anvil cell at 184(5) GPa through a direct reaction of a nickel powder with carbon from the diamond anvils upon heating at 3500 (200) K. Ni3C has the cementite-type structure (Pnma space group, a = 4.519(2) angstrom, b = 5.801(2) angstrom, c = 4.009(3) angstrom), which was solved and refined based on in-situ synchrotron single-crystal X-ray diffraction. The pressure-volume data of Ni3C was obtained on decompression at room temperature and fitted to the 3rd order Burch-Murnaghan equation of state with the following parameters: V-0 = 147.7(8) angstrom(3), K-0 = 157(10) GPa, and K-0 = 7.8(6). Our results contribute to the understanding of the phase composition and properties of Earths outer core.

Ämnesord

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

Nyckelord

nickel carbide; high pressures; X-ray diffraction; equation of state; Earths outer core

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)