Solubility Parameter

• Definition

  Solubility parameter is an index that is used to see if a solute is soluble in solvent. In order to dissolve a solute in a solvent, there should exist an attractive force between a solute and a solvent molecule, equal to the attractive force either between solutes or between solvent molecules. However, it can be referred to as the energy required to separate one(1) molecule from a group of respective molecules. This energy is cohesive energy. Cohesive energy per unit volume is called cohesive energy density (CED). The square root of CED is called solubility parameter (δ). Two substances with similar solubility parameters have energy for covariance, sufficient enough to mix the two substances. On the other hand, two substances with different solubility parameters require far more energy for dispersion than that for mix. Therefore, it brought about the unmixable result. The following is the formula to represent solubility parameter.
  
  R is the ideal gas constant. ΔH_vap is the heat of vaporization. LMV is the liquid molar volume.

  For solubility parameter, the phase is liquid. Therefore, for other phases such as gas or solid, it shows the value at the following temperature and pressure.
  In case of liquid at 298.15K: 298.15K, 1bar
  In case of gas at 298.15K: Boiling point, 1 bar
  In case of solid at 298.15K: Melting point, pressure at triple point

• Estimation Method

  - MolInstincts: The Property value is estimated by the combination of fundamental thermodynamic theories, modern modeling approaches, QSPR (quantitative structure-property relationships) methods, and ANN (Artificial Neural Network) with over fitting prevention algorithm, utilizing the quantum chemical calculations results and molecular descriptors. The estimated value is finally determined after manual inspection.

• Supplementary Explanation on Accuracy

  Comment	Meaning of Comment
  ≤ 1%	0 ≤ abs%error ≤ 1
  ≤ 3%	1 < abs%error ≤ 3
  ≤ 5%	3 < abs%error ≤ 5
  ≤ 10%	5 < abs%error ≤ 10
  ≤ 20%	10 < abs%error ≤ 20
  ≤ 50%	20 < abs%error ≤ 50
  > 50%	abs%error > 50
  Exp. Data Unavailable	Experimental Data are Unavailable

  Where absolute % error means the absolute value of {(experimental value)-(calculated value)}/(experimental value).