Knowledge Bank

When an alkali halide disk, i.e., infrared pressed pellet, containing a small amount of sodium or potassium formate was heated at about $250\circ C$, pronounced changes in the infrared spectrum of the sample were observed. These changes were not due to the decomposition of the solute but to changes in the structure of the ion caused by solid solution formation. Large shifts in the C-H Stretch and in-plane bend fundamentals as well as marked changes in the relative intensities of the antisymmetric and symmetric C-O stretch fundamentals indicated that the structure of the distorted ion was significantly different from that of the normal ion. Isotopic frequencies of the distorted ion have been obtained, and its geometry has been estimated from them.