DOI: 10.6076/d1tp4s
title: Transport and structural properties of reduced S-bearing glasses and melts

description: Elucidating the role of sulfur on the structure of silicate glasses and
 melts at elevated pressures and temperatures is important for
 understanding transport properties, such as electrical conductivity and
 viscosity, of magma oceans and mantle-derived melts. These properties are
 fundamental to modeling the evolution of terrestrial planets and moons.
 Despite several investigations of sulfur speciation in glasses, questions
 remain regarding the effect of S on complex glasses at highly reducing
 conditions relevant to Mercury. Glasses were synthetized with compositions
 representative of the Northern Volcanic Plains of Mercury and containing
 quantities of S as high as 5 wt.%. Multiple spectroscopic methods and
 microprobe analyses were employed to probe the glasses, including in situ
 impedance spectroscopy at 2- and 4-GPa pressures and temperatures up to
 1740 K using a multi-anvil press, 29Si NMR spectroscopy, and Raman
 spectroscopy. Electrical activation energies (Ea) in the glassy state
 range from 0.56 to 1.10 eV, in agreement with sodium as the main charge
 carrier. The electrical measurements suggest that sulfide improves Na+
 transport and may overcome a known impeding effect of the divalent cation
 Ca2+. The glass transition temperature lies between 700-750 K, and for
 temperatures up to 970 K Ea decreases (0.35-0.68 eV) and the
 conductivities of the samples converge (~5-8 ×10-3 S/m). At Tquench, the
 melt fraction is 50-70% and melt conductivity varies from 0.7 to 2.2 S/m,
 with the sample containing 5 wt.% S the most conductive among the set.
 29Si NMR spectra reveal that a high fraction of S bonds with Si in these
 complex glasses, an important insight that has not been recognized
 previously. Raman spectra and maps reveal regions rich in Ca-S or Mg-S
 bonds. The evidence of sulfide interactions with both Si and Ca/Mg suggest
 that alkaline earth sulfides can be considered weak network modifiers in
 these glasses, under highly reduced conditions.  
description: Experimental data from impedance spectroscopy, NMR spectroscopy,
 Raman spectroscopy and electron microprobe analyses. 
 The description of the experiments and analyses is explained the
 manuscript.
description: # Title of Dataset Data used in manuscript GCA-D-23-00571 entitled
 “Experimental Investigation of the Bonding of Sulfur in Highly Reduced
 Silicate Glasses and Melts” by A. Pommier, M. J. Tauber, H. Pirotte, G.D.
 Cody, A. Steele, E.S. Bullock, B. Charlier, and B.O. Mysen (Geochimica et
 Cosmochimica Acta). The spreadsheet lists all the measurements shown in
 the figures of the manuscript. Each tab correspond to a figure: -Figures 2
 and 3: electron microprobe analyses. -Figures 4 and 5: impedance
 spectroscopy -Figure 6: NMR spectroscopy -Figures 8 and 9: Raman
 spectroscopy -Figure 10: NBO/T estimates The reader is referred to the
 manuscript for details about the experimental procedures and results. ##
 Description of the data and file structure * Figure 2 tab: Each sample
 name starts with BBC. For each sample, electron microprobe analyses are
 shown for traverses across the sample and the content of each oxide is in
 wt.%. * Figure 3 tab: Microprobe traverse in sample BBC16. The content of
 each oxide is in wt.%. * Figure 4: Impedance spectra of samples BBC13 and
 BBC17 at selected temperatures. For each temperature, the different
 columns correspond to the frequency, time, real component (Z') and
 imaginary component (Z"). * Figure 5 tab: electrical resistance (R)
 and conductivity (EC) of different samples as a function of temperature
 (T). Each sample name starts with BBC. For each sample, the different
 columns correspond to temperature (in degC and K), inverse T, resistance,
 conductivity and Ln (conductivity). * Figure 6: NMR spectra for four
 starting glasses (VT48, 52, 53, 54). The first column is the chemical
 shift, and the other columns correspond to the intensity of each sample. *
 Figure 7: Raman spectrum of starting glass VT55. The first column is the
 Raman shift, and the second column corresponds to the intensity of the
 sample. * Figure 8: Raman spectra of sulfide components in starting glass
 VT52 and samples from experiments BBC17 and BBC18. For each sample, the
 first column is the Raman shift, and the second column corresponds to the
 intensity of the sample.