I Lab Services 

ACD/Solubility prediction has the following features: 

Compounds subdivided into classes with separate prediction equations for each, including 

new parameters for internal hydrogen bonds. 

The following parameters are used in correlation equations: boiling point, logP/logD, MW, 

MolVol, HydBonding (number of H acceptors and H donors), and refractive index. 

Prediction is not sensitive to the melting point presence for many classes of compounds.  

Even information such as whether the compound is a solid or liquid at room temperature is 

useful in the prediction. 

4.22.1 Limitations 

The general ACD/Solubility algorithm does not calculate the solubility values for the following 

chemical structures: 

Charged structures containing IV valent Nitrogen (+); 

Structures containing atoms other than C, H, O, S, N, and F in possible chemical 

surroundings or structures containing atoms P, Cl, Br, I, Se, Si, Ge, Pb, Sn, As, and B that 

are not within the chemical surroundings shown below (note that A denotes any atom out 

of C, O, S, N, F, or any group listed below

5

): 

A

A

A

A

A

Cl

A 

B

A

Ge

A

P

A

Se

A

6

A

A

A

A

A

A

A

Se

A  

Br

A 

Sn

A

P

A

A

A

A

A

A

A

I

A 

Pb

A

As

A

A

A

Structures that contain elements in their non typical valence; 

Structures with coordinating bonds; and 

Structures containing more than 255 atoms excluding hydrogen (note that the program 

refuses to predict solubility for some cyclic compounds having less than 255 atoms due to 

the fact that the program uses cycle breaking algorithm that increases the number of 

atoms). 

The program does not take into account the specific features of different geometric isomers, 

stereoisomers, conformers, isotopes and structures with non covalent bonds. 

5

 This group cannot be a part of a cycle unless otherwise stated. 

6

 This fragment can be a part of an aromatic cycle. 

ACD/I Lab via ChemSketch  

User's Guide 

53