Cosmochemical Characteristics of the Elements
Channel: Dominik Hezel
Date: 12/04/2023

The chemical elements are broadly classified into what is called their ›cosmochemical character‹. This consists of two properties: (i) the 50% condensation temperature (T50%), and (ii) whether an element is lithophile or siderophile/chalcophile. Elements with T50% above 1400 K are called ›refractory‹ elements. The most important lithophile refractory elements are Al, Ca, Ti and the REE. The more important siderophile refractory elements are W, Ir and Pt. Elements with T50% between 1250 and 1400 K are called ›main‹ elements, as the 3 main elements Mg, Si and Fe condense in this interval. An additional important lithophile main element is Cr. Additionally important siderophile main elements are Ni and Co. Elements with T50% between  640 and 1250 K are called ›volatile‹ elements. The most important lithophile volatile elements are Mn, Na and P. Important siderophile volatile elements are S and Cu. Elements with T50% below 640 K are called ›highly volatile‹ elements. The most important lithophile highly volatile elements are H, O, C, and the noble gases. The most important siderophile highly volatile element is Pb. Interestingly, although O is a highly volatile element, it condenses as the first element together with Al in the most refractory phase corundum. This illustrates the important fact that not only the T50% is important, but also the phase into which an element condenses.