Periodic trends in element enrichments in Pacific manganese nodules: the role of lattice energies

Abstract

Trends in element enrichments in Pacific ferromanganese nodules are reported and are discussed in terms of the element's position in the periodic table and its likely charge state in the solid phase. It is shown that the major thermochemical term governing the partitioning of elements between seawater and ferromanganese oxides is the lattice energy. Lattice energies of elements throughout the periodic table were derived either from thermodynamic cycles or from the Kapustinskii equation. A good correlation between log U and log K p (the manganese nodule-seawater partition coefficient) was found to exist for the 51 elements examined. The observation that lattice energy and solid phase enrichment are closely related is consistent with the claim of Turner and Whitfield (Nature, 279 (1981) 468–469) that an element's solid state chemistry controls its destiny in the marine environment.