| $\mathrm{\Delta }{S}_{\text{mix}\text{ }}$ | Mixing Entropy | $\mathrm{\Delta }{S}_{\text{mix}\text{ }}=-R{\mathrm{\Sigma }}_{i}{c}_{i}\mathrm{l}\mathrm{n}{c}_{i}$ | Enthalpy change of a system when different components are mixed to form a homogeneous system. | [71] |
| $\mathrm{\Delta }{H}_{\text{mix}\text{ }}$ | Mixing Enthalpy | $\mathrm{\Delta }{H}_{\text{mix}\text{ }}={E}_{\text{HEC}\text{ }}-{\sum }_{i} {c}_{i}{E}_{i}$ | The sum of the interaction energy differences in the ideal state. | [72] |
| $\mathrm{\Omega }$ | Entropy-Enthalpy Balance Factor | $\mathrm{\Omega }=\frac{{T}_{\mathrm{m}}\mathrm{\Delta }{S}_{\text{mix}\text{ }}}{\left|\mathrm{\Delta }{H}_{\text{mix}\text{ }}\right|}$ | Tm is the isothermal temperature. | [73] |
| $\delta $ | Atomic (ion) Radius Difference | $\delta ={\left[{\sum }_{i} {c}_{i}\left(1-\frac{{r}_{i}}{\stackrel{‾}{r}}\right)\right]}^{1/2},\stackrel{‾}{r}={\sum }_{i} {c}_{i}{r}_{i}$ | Contribution of differences in atomic/ionic radii of components to lattice distortion | [74] |
| $\mathrm{\Delta }\chi $ | Electronegativity Difference | $\mathrm{\Delta }\chi =\sqrt{{\sum }_{i} {c}_{i}{\left({\chi }_{i}-\stackrel{‾}{\chi }\right)}^{2}},\stackrel{‾}{\chi }={\sum }_{i} {c}_{i}{\chi }_{i}$ | $\mathrm{\Delta }\chi $ reflects the difference in electronegativity between different elements. | [75] |
| VEC | Valence Electron Concentration | $VEC={\sum }_{i} {c}_{i}VE{C}_{i}$ | Reflects the degree of electron filling and energy band structure characteristics of the system | [74] |
| DEED | Disordered Enthalpy-Entropy Descriptor | $DEED=\sqrt{\frac{{\sigma }_{\mathrm{\Omega }}^{-1}\left[{H}_{\mathrm{f}}\right]}{{⟨\mathrm{\Delta }{H}_{\mathrm{h}\mathrm{u}\mathrm{l}\mathrm{l}}⟩}_{\mathrm{\Omega }}}}$ | Predicting the possibility of single-phase disordered structures in multicomponent systems, Hf and Hhull are the DFT formation energies of the partial occupation POCC tiles and the convex hull, respectively. | [76] |
| EFA | Entropy Forming Ability | $EFA={\left[\frac{\left({\sum }_{i=1}^{n} {g}_{i}\right)-1}{{\sum }_{i=1}^{n} {g}_{i}{\left({H}_{i}-{H}_{\text{mix}\text{ }}\right)}^{2}}\right]}^{1/2}$ | Entropy-driven formation of stable single-phase solid solutions, where n is the total number of sampled geometrical configurations and gi are their degeneracies. Hi of the sampled configurations. | [66] |
| LDI | Lattice Distortion Index | $LDI={\sum }_{i=1}^{n} \sqrt{{\left({x}_{i,a}-{x}_{i,0}\right)}^{2}+{\left({y}_{i,a}-{y}_{i,0}\right)}^{2}+{\left({z}_{i,a}-{z}_{i,0}\right)}^{2}}/n$ | Parameters for the degree of lattice distortion in disordered systems, ( x,y,z ) is the atomic position. | [77] |
| $\gamma $ | The normalized geometric packing parameter for the metallic sublattice calculated | $\gamma =\left\{1-{\left[1-\frac{{\left({r}_{\mathrm{S}}+\stackrel{‾}{r}\right)}^{2}-{\stackrel{‾}{r}}^{2}}{{\left({r}_{\mathrm{S}}+\stackrel{‾}{r}\right)}^{2}}\right]}^{1/2}\right\}/\left\{1-{\left[1-\frac{{\left({r}_{\mathrm{L}}+\stackrel{‾}{r}\right)}^{2}-{\stackrel{‾}{r}}^{2}}{{\left({r}_{\mathrm{L}}+\stackrel{‾}{r}\right)}^{2}}\right]}^{1/2}\right\}$ | Evaluating how different metal atoms stack together in a crystal lattice, where rS and rL are the radii of the smallest and largest atoms. | [78] |
