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1. Condensation and the Volatility Trend of the Earth

   https://doi.org/10.1007/s11214-025-01182-6  

   Lodders, Katharina; Fegley, Bruce; Mezger, Klaus; Ebel, Denton (June 2025, Space Science Reviews)

   Abstract This article describes condensation of the elements and use of condensation temperatures to plot and interpret Earth’s apparent volatility trend. Major points covered include the following. (1) Updated 50% condensation temperatures (T₅₀) for all naturally occurring elements, Tc, and Pu are tabulated at 10⁻²to 10⁻⁸bar total pressure for solar composition material. (2) Condensation temperatures are mainly controlled by the Gibbs energy of condensation reactions and also by the Gibbs energy of ideal mixing if elements (compounds) condense in a solution. The additional Gibbs energy change due to non-ideal solution, i.e., activity coefficients ≠1, is a secondary effect. (3) The theoretically correct relationship between condensation temperature and fraction condensed ($$\alpha _{\mathrm{M}}$$ ${\alpha }_M$) is derived from mass balance and chemical thermodynamic considerations. For major elements the condensation temperature is inversely proportional to log (1-$$\alpha _{\mathrm{M}}$$ ${\alpha }_M$). For trace elements dissolving in solid solution the condensation temperature is inversely proportional to log [(1-$$\alpha _{\mathrm{M}}$$ ${\alpha }_M$)/$$\alpha _{\mathrm{M}}$$ ${\alpha }_M$]. (4) The maximum amount of element condensed per K⁻¹, i.e., the maximum in [d$$\alpha _{\mathrm{M}}$$ ${\alpha }_M$/d(1/T)] is at the inflection point in the logistic (sigmoid) curve for an element, which is also at (or close to) the 50% condensation temperature. (5) Plots of normalized elemental abundances versus 50% condensation temperatures (volatility trends) are qualitative indicators of elemental fractionations due to volatility because they do not use the theoretically correct and quantitative relationship between condensation temperature and fraction condensed. (6) Volatility trend plots for average elemental abundances in CM, CO, CV, CR, H, L, LL, EH, EL chondrites show different “trends” for moderately and highly volatile elements, which may be linear, curved, a step function, or plateau. A comparison of three abundance sets for CM and CV chondrites shows trends depend on which elements are plotted, which data sources are used, and which temperature range is considered. (7) Proposed mechanisms for volatile element depletion in carbonaceous chondrites and the Earth are reviewed. (8) Some possible implications of volatile element abundances in the bulk silicate Earth are discussed. 

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2. Thermal performance and condensation risk of single-pane glazing with low emissivity coatings

   https://doi.org/10.1557/adv.2020.160  

   Duan, Qiuhua; Zhao, Yuan; Wang, Julian (March 2020, MRS Advances)

   ABSTRACT To understand the potential impacts on both thermal performance and condensation risks of using low-e coatings in buildings, especially in the single-pane sector, in this work, parametric numerical analysis in winter is conducted. Three building glazing models, including the single-pane without low-e coatings (SNL), single-pane with exterior low-e coatings (SEL), and single-pane with interior low-e coatings (SIL), are selected and simulated through COMSOL over a range of outdoor temperature and indoor humidity. The temperature of the interior surface of windows, heat flux through windows, winter U-factor of center-of-glass will be obtained and compared. Additionally, a numerical code is developed in R to compute and plot the condensation temperatures of these three models upon the given indoor humidity levels and simulated surface temperatures. The comprehensive analysis of condensation risks on the glazing inner surface of the three models will be conducted. This parametric simulation effort indicates an interesting feature for a single-pane window: while the SIL gives a substantially lower U than the SNL, it also corresponds to an increased condensation risk under certain limits of external temperature and indoor humidity levels. Upon the resultant condensation temperatures and thermal performance analysis, we can conclude the parameters of the windowpane property, coating emissivity and placement, local climate, and building interior thermal settings must be taken into account collectively when it comes to adding low-e coatings to single-pane windows. 

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3. Effects of Metallicity on Graphite, TiC, and SiC Condensation in Carbon Stars

   https://doi.org/10.3847/1538-4357/adc40f  

   Adams, Gabrielle M; Lodders, Katharina (May 2025, The Astrophysical Journal)

   Abstract From transmission electron microscopy and other laboratory studies of presolar grains, the implicit condensation sequence of carbon-bearing condensates in circumstellar envelopes of carbon stars is (from first to last) TiC-graphite-SiC. We use thermochemical equilibrium condensation calculations and show that the condensation sequence of titanium carbide (TiC), graphite (C(Gr)), and silicon carbide (SiC) depends on metallicity in addition to C/O ratio and total pressure. Calculations were performed for a characteristic carbon star ratio of C/O = 1.2 from 10⁻¹⁰to 10⁻⁴bars total pressure and for uniform metallicity variations ranging from 0.01 to 100 times solar elemental abundances. TiC always condenses at higher temperatures than SiC, and the carbide condensation temperatures increase with both increasing metallicity and increasing total pressure. Graphite, however, can condense in a cooling circumstellar envelope before TiC, between TiC and SiC, or after SiC, depending on the carbon-bearing gas chemistry, which is dependent on metallicity and total pressure. Analytical expressions for the graphite, TiC, and SiC condensation temperatures as functions of metallicity and total pressure are presented. The inferred sequence from laboratory presolar grain studies, TiC-graphite-SiC, is favored under equilibrium conditions at solar and subsolar metallicities between ∼10⁻⁵and 10⁻⁸bar total pressure within circumstellar envelopes of carbon stars with nominal C/O = 1.2. We also explored the dependence of the sequence at C/O ratios of 1.1 and 3.0, and found that as the C/O ratio increases, the TiC-graphite-SiC condensation sequence region occurs toward higher total pressures and lower metallicities. 

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4. Solar system abundances and condensation temperatures of the halogens fluorine, chlorine, bromine, and iodine

   https://doi.org/10.1016/j.chemer.2023.125957  

   Lodders, Katharina; Fegley, Bruce (April 2023, Geochemistry)

   We review a large body of available meteoritic and stellar halogen data in the literature used for solar system abundances (i.e., representative abundances of the solar system at the time of its formation) and associated analytical problems. Claims of lower solar system chlorine, bromine and iodine abundances from recent analyses of CI-chondrites are untenable because of incompatibility of such low values with nuclear abundance systematics and independent measurements of halogens in the Sun and other stars. We suspect analytical problems associated with these peculiar rock types have led to lower analytical results in several studies. We review available analytical procedures and concentrations of halogens in chondrites. Our recommended values are close to pre-viously accepted values. Average concentrations by mass for CI-chondrites are F = 92 ± 20 ppm, Cl = 717 ± 110 ppm, Br = 3.77 ± 0.90 ppm, and I = 0.77 ± 0.31 ppm. The meteoritic abundances on the atomic scale normalized to N(Si) =106 are N(F) = 1270 ± 270, N(Cl) = 5290 ± 810, N(Br) = 12.3 ± 2.9, and N(I) = 1.59 ± 0.64. The meteoritic logarithmic abundances scaled to present-day photospheric abundances with log N(H) = 12 are A(F) = 4.61 ± 0.09, A(Cl) = 5.23 ± 0.06, A(Br) = 2.60 ± 0.09, and A(I) = 1.71 ± 0.15. These are our recommended present-day solar system abundances. These are compared to the present-day solar values derived from sunspots of N(F) = 776 ± 260, A(F) = 4.40 ± 0.25, and N(Cl) = 5500 ± 810, A(Cl) = 5.25 ± 0.12. The recommended solar system abundances based on meteorites are consistent with F and Cl abundance ratios measured independently in other stars and other astronomical environments. The recently determined chlorine abundance of 776 ± 21 ppm by Yokoyama et al. (2022) for the CI-chondrite-like asteroid Ryugu is consistent with the chlorine abundance evaluated for CI-chondrites here. Historically, the halogen abundances have been quite uncertain and unfortunately remain so. We still need reliable measurements from large, representative, and well-homogenized CI-chondrite samples. The analysis of F, Br, and I in Ryugu samples should also help to obtain more reliable halogen abundances. Updated equilibrium 50 % condensation temperatures from our previous work (Lodders, 2003; Fegley and Schaefer, 2010; Fegley and Lodders, 2018) are 713 K (F), 427 K (Cl), 392 K (Br) and 312 K (I) at a total pressure of 10^ 4 bar for a solar composition gas. We give condensation temperatures considering solid-solution as well as kinetic inhibition effects. Condensation temperatures computed with lower halogen abundances do not represent the correct condensation temperatures from a solar composition gas. 

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5. An adaptive biomolecular condensation response is conserved across environmentally divergent species

   https://doi.org/10.1038/s41467-024-47355-9  

   Keyport_Kik, Samantha; Christopher, Dana; Glauninger, Hendrik; Hickernell, Caitlin_Wong; Bard, Jared_A_M; Lin, Kyle_M; Squires, Allison_H; Ford, Michael; Sosnick, Tobin_R; Drummond, D_Allan (April 2024, Nature Communications)

   Abstract Cells must sense and respond to sudden maladaptive environmental changes—stresses—to survive and thrive. Across eukaryotes, stresses such as heat shock trigger conserved responses: growth arrest, a specific transcriptional response, and biomolecular condensation of protein and mRNA into structures known as stress granules under severe stress. The composition, formation mechanism, adaptive significance, and even evolutionary conservation of these condensed structures remain enigmatic. Here we provide a remarkable view into stress-triggered condensation, its evolutionary conservation and tuning, and its integration into other well-studied aspects of the stress response. Using three morphologically near-identical budding yeast species adapted to different thermal environments and diverged by up to 100 million years, we show that proteome-scale biomolecular condensation is tuned to species-specific thermal niches, closely tracking corresponding growth and transcriptional responses. In each species, poly(A)-binding protein—a core marker of stress granules—condenses in isolation at species-specific temperatures, with conserved molecular features and conformational changes modulating condensation. From the ecological to the molecular scale, our results reveal previously unappreciated levels of evolutionary selection in the eukaryotic stress response, while establishing a rich, tractable system for further inquiry. 

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