The interplay between chemistry and thermodynamics determines the final
outcome of the process of gravitational collapse and sets the conditions for
the formation of the first cosmological objects, including primordial
supermassive black holes. In this chapter, we will review the main chemical
reactions and the most important heating/cooling processes taking place in a
gas of primordial composition, including the effects of local and cosmological
radiation backgrounds.Comment: Preprint of the Chapter "Thermodynamics and Chemistry of the Early
Universe", to be published in the review volume "Formation of the First Black
Holes", Latif M. and Schleicher D.R.G., eds., World Scientific Publishing
Company, 2018, pp. [see
http://www.worldscientific.com/worldscibooks/10.1142/10652