Alkoxy-type derivative compounds are a process for preparing alkoxy-type derivatives of trivalent Group 3b metals, e.g., cerium (III), such as alkoxides, siloxides or alkanolatoamines from an anhydrous complex of trivalent Group 3b metals, e.g. cerium ammonium nitrate complex, in the presence of an alcohol, silanol or alkanolamine and a base or by employing the complex and alkali salts of the alcohol, silanol, or alkanolamine.