We have found the Wadsley‐Roth class of crystallographic shear structures in chemical systems based on to undergo lithium insertion reactions at ambient temperature to stoichiometries of 0.4 to 1.4 Li per host metal on reaction with n‐BuLi. For the general case of structures with intersecting shear planes, minimal structural distortion occurs on lithiation even for compounds with the largest block sizes. We report crystal‐chemical data for 14 lithium insertion compounds of this type, and the behavior of selected host compounds mixed with carbon as the positive electrodes in small lithium secondary test cells.