Systematization of crystal field parameters for trivalent rare-earth (RE3+) ions at orthorhombic sites in selected laser materials-standardization approach

► Crucial intrinsic features of orthorhombic CF Hamiltonians presented. ► Comparative analysis and standardization of orthorhombic CF parameters carried out. ► Er3+:SrLaAlO4, Ce3+:Ce2Ge2In, Eu3+:BaFCl, Er3+:LiKGdF5, Eu3+:SBN, Pr3+:K2Pr(Y)Cl5. ► Results facilitate spectroscopic studies of orthorhombic CF parameters for fN ions.