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Abstract Solar photospheric abundances and CI-chondrite compositions are reviewed and updated to obtain representative solar system abundances of the elements and their isotopes. The new photospheric abundances obtained here lead to higher solar metallicity. Full 3D NLTE photospheric analyses are only available for 11 elements. A quality index for analyses is introduced. For several elements, uncertainties remain large. Protosolar mass fractions are H (X = 0.7060), He (Y = 0.2753), and for metals Li to U (Z = 0.0187). The protosolar (C+N)/H agrees within 13% with the ratio for the solar core from the Borexino experiment. Elemental abundances in CI-chondrites were screened by analytical methods, sample sizes, and evaluated using concentration frequency distributions. Aqueously mobile elements (e.g., alkalis, alkaline earths, etc.) often deviate from normal distributions indicating mobilization and/or sequestration into carbonates, phosphates, and sulfates. Revised CI-chondrite abundances of non-volatile elements are similar to earlier estimates. The moderately volatile elements F and Sb are higher than before, as are C, Br and I, whereas the CI-abundances of Hg and N are now significantly lower. The solar system nuclide distribution curves of s-process elements agree within 4% with s-process predictions of Galactic chemical evolution models. P-process nuclide distributions are assessed. No obvious correlation of CI-chondritic to solar elemental abundance ratios with condensation temperatures is observed, nor is there one for ratios of CI-chondrites/solar wind abundances. 

Updated solar photospheric abundances are compared with meteoritic abundances. The uncertainties of solar abundances of many trace elements are considerably reduced compared to the 2003 compilation. Some of the solar rare earth elements have now assigned errors of ± 5%, approaching the accuracy of meteorite analyses. The agreement between solar abundances and CI chondrites is further improved. Problematic elements with comparatively large differences between solar and meteoritic abundances are manganese, hafnium, rubidium, gallium, and tungsten. The CI chondrites match solar abundances in refractory lithophile, siderophile, and volatile elements. All other chondrite groups differ from CI chondrites. With analytical uncertainties, there are no obvious fractionations between CI meteorites and solar abundances. Further progress will primarily come from improved solar abundance determinations. The limiting factor in the accuracy of meteorite abundances is the inherent heterogeneity of CI chondrites, primarily the Orgueil meteorite. The interstellar medium (ISM) from which the solar system formed has the same composition as the Sun for volatile and moderately volatile elements within a factor of 2. The more refractory elements of the ISM are depleted from the gas and are concentrated in grains.