  The chemical equilibrium distribution of 69 elements between gas and melt is
modeled for bulk silicate Earth (BSE) material from 1000 - 4500 K and 1e-6 to
100 bar. The BSE melt is modeled as a non-ideal solution and the effects of
different activity coefficients and ideal solution are studied. Results include
50% condensation temperatures, major gases of each element, and oxygen fugacity
(fO2) of dry and wet BSE material. The dry BSE model excludes H, C, N, F, Cl,
Br, I, S, Se, Te. The wet BSE model includes H and the other volatiles. Key
conclusions are much higher condensation temperatures in silicate vapor than in
solar composition gas at the same total P, a different condensation sequence in
silicate vapor than in solar composition gas, good agreement between different
activity coefficient models except for the alkalis, agreement, where overlap
exists, with prior published work, condensation of Re, Mo, W, Ru, Os oxides
instead of metals, a stability field for Ni-rich metal as reported by Lock et
al. (2018), agreement between ideal solution (from this work and from Lock et
al. 2018) and real solution condensation temperatures for elements with minor
deviations from ideality in the oxide melt, similar 50% condensation
temperatures, within a few degrees, in the dry and wet BSE models for the major
elements Al, Ca, Fe, Mg, Si, and the minor elements Co, Cr, Li, Mn, Ti, V, and
much lower 50 percent condensation temperatures for elements such as B, Cu, K,
Na, Pb, Rb, which form halide, hydroxide, sulfide, selenide, telluride and
oxyhalide gases. The latter results are preliminary because the poorly known
solubilities and activities of volatile elements in silicate melts must be
considered for the correct equilibrium distribution, condensation temperatures
and mass balance of F, Cl, Br, I, H, S, Se and Te bearing species between melt
and vapor (abridged).
