title: Lanthanide contraction over the 4f series follows a quadratic decay.
abstract: An analysis of the structural data available for isotypical series of rare earth compounds shows that the contraction of X-ray determined Ln-O bond distances over the f block is at least quadratic. Such quadratic decay is observed also for Ln(III) ionic radii, calculated bond distances, and lanthanide atomic orbital expectation values.
authors.affiliation: Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, I-56126 Pisa (Italy). quadrelli@cpe.fr
authors.forename: Elsje Alessandra
authors.initials: EA
authors.lastname: Quadrelli