Pauling's Ionicity and Charge-Density Waves in Layered Transition-Metal Dichalcogenides

The crystal distortions commonly observed in the layered transition-metal dichalcogenides have been attributed to a Fermi-surface instability, i.e., a charge-density wave. I find that the temperatures of these distortions correlate with the ionicity of the metal-chalcogen bond. This results suggests that these distortion temperatures can be specified without knowing the details of the Fermi surface.