title: Low-Dimensional Network Formation in Molten Sodium Carbonate.
abstract: Molten carbonates are highly inviscid liquids characterized by low melting points and high solubility of rare earth elements and volatile molecules. An understanding of the structure and related properties of these intriguing liquids has been limited to date. We report the results of a study of molten sodium carbonate (Na2CO3) which combines high energy X-ray diffraction, containerless techniques and computer simulation to provide insight into the liquid structure. Total structure factors (F(x)(Q)) are collected on the laser-heated carbonate spheres suspended in flowing gases of varying composition in an aerodynamic levitation furnace. The respective partial structure factor contributions to F(x)(Q) are obtained by performing molecular dynamics simulations treating the carbonate anions as flexible entities. The carbonate liquid structure is found to be heavily temperature-dependent. At low temperatures a low-dimensional carbonate chain network forms, at T = 1100 K for example ~55% of the C atoms form part of a chain. The mean chain lengths decrease as temperature is increased and as the chains become shorter the rotation of the carbonate anions becomes more rapid enhancing the diffusion of Na(+) ions.
authors.affiliation: Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Wilding
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Wilson
authors.affiliation: X-ray Science Division, Argonne National Laboratory, Argonne IL60439, USA.|Materials Development, Inc., Arlington Heights IL 60004, USA.
authors.forename: Oliver L G
authors.initials: OL
authors.lastname: Alderman
authors.affiliation: X-ray Science Division, Argonne National Laboratory, Argonne IL60439, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Benmore
authors.affiliation: X-ray Science Division, Argonne National Laboratory, Argonne IL60439, USA.|Materials Development, Inc., Arlington Heights IL 60004, USA.
authors.forename: J K R
authors.initials: JK
authors.lastname: Weber
authors.affiliation: Geosciences Department and Department of Chemistry, Stony Brook University, NY 11794-2100, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Parise
authors.affiliation: Materials Development, Inc., Arlington Heights IL 60004, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Tamalonis
authors.affiliation: X-ray Science Division, Argonne National Laboratory, Argonne IL60439, USA.|Materials Development, Inc., Arlington Heights IL 60004, USA.|Geosciences Department and Department of Chemistry, Stony Brook University, NY 11794-2100, USA.
authors.forename: Lawrie
authors.initials: L
authors.lastname: Skinner