The ever-growing requirement to develop new materials for highly specific applications is making major demands for thermodynamic data which have not, to date, been measured. This, in turn, means that, increasingly, estimated values are required to make thermodynamic interpretations and feasibility studies of reactions involving these materials. In this vein, four further extensions of, and insights into, the Thermodynamic Solvate Difference Rule, are presented here and tested. The result is the provision of valuable, albeit approximate, rules useful for many areas of organic/inorganic chemisty to predict thermodynamic data in cases where experimental data have not yet been determined. These extended rules take the form P{M(p)X(q).jL,p} + P{M(p)'X(q')'.kL,p} approximate to P{M(p)X(q).dL,p} + P{M(p)'X(q')'.sL,p} where j + k = d + s and the salt M(p)'X(q)' can be the same as M(p)X(q). P represents any of the individual thermodynamic properties: Delta(f)H degrees, Delta(f)G degrees, Delta(f)S degrees, etc. Also P{M(p)X(q).jL,p} + P{M(p)'X(q')'.kL,p} approximate to P{M(p)X(q).kL,p} + P {M(p)'X(q')'.jL,p} For salts M(p)X(q), M(p)'X(q)', and M(r)'X(s)' and then for multiple salts compounded from these, where one salt is considered to be the "solvent" of the other, and vice-versa, then P{M(p)X(q).jM(r)'X(s)',s} approximate to P{M(p)X(q),s} + j.Theta(P){M(r)'X(s)',s - s} P{M(r)',X(s)'.dM(p)X(q),s} approximate to P{M(r)'X's,s} + d.Theta(P){M(p)X(q),s - s} where Theta(P){M(r)'X(s)', s-s} and Theta(P){M(p)X(q),s-s} are constants, independent of the nature of M(p)X(q) and M(r)'X(s)', respectively. Thus, salts may e permuted as being regarded as solvent and solvate. A cascading rule can be established as follows P{M(p)X(q).M(p)'X(q)'.jM(r)'X(s)',s} approximate to P{M(p)X(q).M(p)'X(q)',s} + j.Theta(P){M(r)'X(s)',s-s} approximate to P {M(p)X(q)'s} + Theta(P){M(p)'X(q)',s-s} + j.Theta(P){M(r)'X(s)',s-s} and permutationps Lreon. Developed and applied initially for inorganic compounds, the rule is shown to extend into the arena of organic thermochernistry.