Cryptand is one of the most important members of the cryptand family of chelating agents.In Nomenclature of Inorganic Chemistry (2005), IUPAC recommends the abbreviation 'crypt-222'. Cryptand is one of the most important members of the cryptand family of chelating agents.In Nomenclature of Inorganic Chemistry (2005), IUPAC recommends the abbreviation 'crypt-222'.