I'm reading a research article about a model trying to explain the elemental compositions of meteorites.
What confuses me, are statements of the following type (here in chapter 2.1, second paragraph about enstatite chondrites, a type of meteor):
[...] Enstatite condrites contain minerals that are remarkably reduced chemically, including abundant sulfides like oldhamite (CaS).
In my understanding reduction or oxidization only refers to a specific element in a specific reaction, but here they talk about a compound with unknown reaction path to form it.
- How can CaS be considered to be (remarkably) reduced, if it is not an element in a reaction?
- How can CaS be considered to be (remarkably) reduced, if we don't know the reaction path that it formed in?
- Steven J. Desch, Anusha Kalyaan, Conel M. O'D. Alexander. The Effect of Jupiter's Formation on the Distribution of Refractory Elements and Inclusions in Meteorites. arXiv:1710.03809 [astro-ph.EP]