Martínez Pérez, ÁlvaroMolina, Edil D.Rodríguez, José M.Sigarreta, José M.2026-04-102026-04-10202510.2298/FIL2509069Mhttps://hdl.handle.net/20.500.14352/134640Topological indices are used to understand physicochemical properties of chemical compounds, since they capture some properties of a molecule in a single number. The aim of this paper is to obtain new results for the Sum Lordeg Index. We provide some relations between the Sum Lordeg Index and other classic topological indices. Moreover, we show upper and lower bounds for this topological index on unicyclic graphs and find the corresponding extremal graphs. Finally, we show that the Sum Lordeg Index is an important tool for predicting the boiling point of cycloalkanes isomers.engjournal articlehttps://doi.org/10.2298/FIL2509069Mopen accessSum Lordeg IndexUnicyclic graphGraph invariantVertex-degree-based graph invariantTopological indexCiencias12 Matemáticas