Among the triatomic molecules/ions, BeClX2, NX3X−, NX2O, NOX2X+, OX3, SClX2, IClX2X−, IX3X− and XeFX2, the total number of linear molecule(s)/ion(s) where the hybridization of the central atom does not have contribution from the d-orbital(s) is. [Atomic numbers: S =16, Cl =17, I =53 and Xe =54]