Table 2. Details of four most important descriptors were used in model construction .

Symbol	Descriptor Block	Description
RDF030u	Radial Distribution Function descriptors	Radial Distribution Function - 030 / unweighted
LP1	Topological (2D matrix-based descriptors)	Lovasz-Pelikan index (leading eigenvalue)
EEig02x	Topological (Edge adjacency indices)	Eigenvalue 02 from edge adj. matrix weighted by edge degrees
Mor04p	3D-MoRSE	Signal 04 / weighted by polarizability