In transition state theory, the kinetics and thermodynamics of most reactions are controlled by the height of the transition state barrier and the difference in energy level between the reactants and the products. Some reactions have very high energy barriers such that extreme conditions are nee...

High pressure chemistry tend to return compounds with very interesting and unusual bonding structures, such as $\ce{NaCl7}$ and $\ce{Na2He}$ However, for most of these, the resulting product is only at best metastable (e.g. diamond) when returning to ambient conditions, and does not survive when...

There. And there. Almost a year ago, a group of scientists claimed to have reached compounds of $\ce{Na}$ and $\ce{Cl}$ with weird stochiometries ($\ce{NaCl3, Na3Cl, NaCl7, Na3Cl2}$ and $\ce{Na2Cl}$). What one of the articles says: These compounds are thermodynamically stable and, once made,...

For all nomenclature purposes, one should refer to the official IUPAC recommendations, which in this case are laid down in Nomenclature of Inorganic Chemistry — IUPAC Recommendations 2005, the ‘Red Book’. The relevant section for this question is section IR-5: Compositional Nomenclature, and Over...