The exponential growth of population and industrial development necessitates the deployment of monitoring and sensing devices to curb the rising concentration of toxic gases in the environment. In the present work, the density functional theory approach has been employed on the chromium selenosulfide (CrSSe) monolayer. The structural stability of CrSSe monolayer was verified from the calculation of cohesive energy ( \(-\) 2.11 eV/atom) and dynamical stability was stated based on the phonon dispersion curves with no imaginary frequencies. CrSSe monolayer has metallic behaviour which can verified from the electronic band structure and density of states (DOS). Apart from that, gas sensing properties of CrSSe monolayer for some oxide gases such as NO2, CO were calculated. From the selected gas molecules for the current study, it has been analysed that NO2 gas molecule having adsorption energy \(-\) 0.772 eV, acts as acceptor with 0.112e charge transferred from the CrSSe monolayer and work function difference is \(-\) 0.0541 eV. Majority of the contribution by NO2 gas molecule is in the valence band which can be checked from projected density of states (PDOS). In the investigation of CrSSe monolayer as a sensing material it has been verified that material shows remarkable sensitivity for the NO2 gas molecule.
