Following above mentioned structural information, we started our calculations by structural optimization after performing a careful convergence test. The same convergence criteria are met for all the monolayers. The optimized structure of the monolayer is shown in Fig. . The calculated values of lattice constants (a = b) for CrS 2 , CrSe 2 and Janus CrSSe is 3.05, 3.23, and 3.14Å , respectively. The corresponding bond length between Cr-S and Cr-Se are 2.30 and 2.45 Å for CrS 2 and CrSe 2 , respectively. Meanwhile, the bond length between Cr-S and Cr-Se in Janus CrSSe is 2.31 and 2.44 Å respectively. Similarly, the interlayer distance between two X atoms at the top layer and bottom layer gives the thickness (ℎ) of the monolayer which are 2.97, 3.17, and 3.07 Å for CrS 2 , CrSe 2 and Janus CrSSe monolayers, respectively. In addition, the bond angle between S-Cr-S, Se-Cr-Se, and S-Cr-Se in these respective monolayers are 80.31°, 80.71°, and 80.45°. The computed structural properties of all three monolayers are shown in Table , which are in good agreement with the available literature . Our results demonstrate that the optimized lattice parameter, bond length, bond angle, and thickness are in the order of CrS 2 < CrSSe< CrSe 2 . The optimized values of the structural parameters of the Janus CrSSe monolayer are in between CrS 2 and CrSe 2 monlayers.