Components of ideal solutions

For components of ideal solutions, the activity of each component is taken to be the ratio of its molar concentration to a standard concentration of 1 M, so the units... 

It can be noticed that a linear behaviour of both thermodynamic p>arameters AH" and AS" versus 5, can be related to a random distribution of non-interacting point defects as components of ideal solution. Generally, when the nonstoichiometiy increases, noticeable deviation from linearity can be observed. In the case of Ndi.95Ni04+6 oxide, ideal-solutionlike state means that the interaction among defect species is nearly constant regardless of the defect concentration. 

---