N.B.! These descriptors can be only used for model devel= opment on OCHEM web site and cannot be exported.
Most of Chemaxon descriptors (also known as: Chemaxon calculators) are i= mplemented in OCHEM platform and can be calculated for any set of molecules= . Desscriptors implemented are those which return munerical or boolean resu= lts. Unimplemented descriptors are those which return results not suitable = for modeling purposes such as molecules, formula, or fingerprints. Also cal= culators that require specific input parameters are not implemented. Exampl= e of these calculators are those that check whether certain atom is assymet= ric, whether 2 atoms are connected, or calculate the angle between 3 specif= ied atoms.
The implemented descriptors are divided into 7 groups: Elemental Analysi= s, Charge, Geometry, Partitioning, Protonation, Isomers, and Others
| Descriptor Name | Descriptor class | Definition | Considers pH during calculation= |
| atomcount | Elemental Analysis | Number of atoms in the molecule | no |
| exactmass | Elemental Analysis | Exact molecule mass calculation based on the mos= t frequent natural isotopes of the elements | no |
| mass | Elemental Analysis | Molecule mass calculation | no |
| no | |||
| averagemolecularpolarizability | Charge | Average molecular polarizability calculation | yes |
| formalcharge | Charge | Formal charge calculation | yes |
| molecularpolarizability | Charge | Molecular polarizability calculation | yes |
| no | |||
| aliphaticatomcount | Geometry | Aliphatic atom count | no |
| aliphaticbondcount | Geometry | Aliphatic bond count | no |
| aliphaticringcount | Geometry | Aliphatic ring count | no |
| aliphaticringcountofsize | Geometry | Aliphatic ring count of size | no |
| aromaticatomcount | Geometry | Aromatic atom count | no |
| aromaticbondcount | Geometry | Aromatic bond count | no |
| aromaticringcount | Geometry | Aromatic ring count | no |
| aromaticringcountofsize | Geometry | Aromatic ring count of size | no |
| asymmetricatomcount | Geometry | The number of asymmetric atoms | no |
| balabanindex | Geometry | The Balaban index | no |
| bondcount | Geometry | Bond count | no |
| carboaliphaticringcount | Geometry | Carboaliphatic ring count | no |
| carboaromaticringcount | Geometry | Carboaromatic ring count | no |
| carboringcount | Geometry | Carbo ring count | no |
| chainatomcount | Geometry | Chain atom count | no |
| chainbondcount | Geometry | Chain bond count | no |
| chiralcentercount | Geometry | The number of tetrahedral stereogenic center ato= ms | no |
| dreidingenergy | Geometry | Calculates the dreiding energy of a conformer of= the molecule in kcal/mol | no |
| fragmentcount | Geometry | Fragment count | no |
| fusedaliphaticringcount | Geometry | The number of fused aliphatic rings (SSSR smalle= st set of smallest aliphatic rings) | no |
| fusedaromaticringcount | Geometry | The number of fused aromatic rings (SSSR smalles= t set of smallest aromatic rings) | no |
| fusedringcount | Geometry | The number of fused rings (SSSR smallest set of = smallest rings) | no |
| hararyindex | Geometry | Harary index | no |
| heteroaliphaticringcount | Geometry | Heteroaliphatic ring count | no |
| heteroaromaticringcount | Geometry | Heteroaromatic ring count | no |
| heteroringcount | Geometry | Hetero ring count | no |
| hyperwienerindex | Geometry | Hyper Wiener index | no |
| largestringsize | Geometry | Largest ring size | no |
| largestringsystemsize | Geometry | Largest ring system size | no |
| maximalprojectionarea | Geometry | Calculates the maximal projection area | no |
| maximalprojectionradius | Geometry | Calculates the maximal projection radius | no |
| maximalprojectionsize | Geometry | no | |
| minimalprojectionarea | Geometry | Calculates the minimal projection area | no |
| minimalprojectionradius | Geometry | Calculates the minimal projection radius | no |
| minimalprojectionsize | Geometry | no | |
| molecularsurfacearea | Geometry | Molecular Surface Area calculation (3D) | yes |
| plattindex | Geometry | The Platt index | no |
| randicindex | Geometry | The Randic index | no |
| polarsurfacearea | Geometry | Topological Polar Surface Area calculation (2D)<= /td> | yes |
| ringatomcount | Geometry | Ring atom count | no |
| ringbondcount | Geometry | Ring bond count | no |
| ringcount | Geometry | Ring count | no |
| ringcountofsize | Geometry | Ring count of size | no |
| ringsystemcount | Geometry | The number of ring systems | no |
| ringsystemcountofsize | Geometry | Ring system count of size | no |
| rotatablebondcount | Geometry | Rotatable bond count | no |
| smallestringsize | Geometry | Size of smallest ring | no |
| smallestringsystemsize | Geometry | Smallest ring system size | no |
| stereodoublebondcount | Geometry | The number of stereo double bonds | no |
| szegedindex | Geometry | Szeged index | no |
| volume | Geometry | Calculate the van der Waals volume of the molecu= le | no |
| wienerindex | Geometry | Wiener index | no |
| wienerpolarity | Geometry | Wiener polarity | no |
| vdwsa | Geometry | Van der Waals Surface Area calculation | yes |
| no | |||
| logp | Partitioning | logP calculation: logP of uncharged species, or,= in the case of zwitterions, logD at pI | no |
| logd | Partitioning | logD calculation | yes |
| no | |||
| isoelectricpoint | protonationDescriptors | Isoelectric point calculation | no |
| no | |||
| doublebondstereoisomercount | Isomers | The number of double-bond stereoisomers of the m= olecule | no |
| stereoisomercount | Isomers | The number of stereoisomers of the molecule | no |
| tautomercount | Isomers | The number of tautomers | no |
| tetrahedralstereoisomercount | Isomers | The number of tetrahedral stereoisomers of the m= olecule | no |
| no | |||
| acceptorcount | Others | Hydrogen bond acceptor atom count in molecule | yes |
| acceptorsitecount | Others | Hydrogen bond acceptor multiplicity in molecule<= /td> | no |
| donorcount | Others | Hydrogen bond donor atom count in molecule | yes |
| donorsitecount | Others | Hydrogen bond donor multiplicity in molecule | yes |
| hmopienergy | Others | HMO Pi energy | yes |
| pienergy * | Others | Pi energy | yes |
| msacc | Others | Hydrogen bond acceptor average multiplicity over= microspecies by pH | no |
| msdon | Others | Hydrogen bond donor average multiplicity over mi= crospecies by pH | no |
| resonantcount | Others | The number of resonant structures | no |
Calculation of some descriptors require consideration of pH value. User = is allowed 3 options for pH:
Descriptors which consider pH value during their calculation are: verage= molecularpolarizability, formalcharge, molecularpolarizability, molecularsu= rfacearea, polarsurfacearea, vdwsa, logd, acceptorcount, acceptorsitecount,= donorcount, donorsitecount, hmopienergy, pienergy
The following descriptors measure the ring size: aliphaticringcountofsiz= e, aromaticringcountofsize, ringcountofsize, ringsystemcountofsize They are= calculated for 3-, 4-, 5-, 6-, 7-, and 8-membered rings.
The following calculators are unable to handle molecules with multiple f= ragments, instead OCHEM platform replaces it with a "missing descripto= r value". Currently this value is set to 0. We plan to allow the user = to specify such value in the future or even skip the whole molecule altoget= her from the dataset.