NdH2O93

NdH2O93 is a chemical formula that is sometimes encountered in discussions of neodymium hydration shells. In theory, it would represent a neodymium(III) ion surrounded by 93 water molecules, written as Nd(H2O)93. In practice, such a discrete, fully hydrated complex is not observed under ordinary laboratory conditions; real neodymium hydrates tend to have far smaller hydration numbers in crystalline or solution forms.

Interpreting NdH2O93 as a coordination compound implies a highly hydrated structure. Neodymium(III) typically forms octa- or nonahydrated aquo complexes in solution, with coordination numbers around 8–9 in common crystallites, while higher hydration numbers occur only in theoretical models or when packed into unusually water-rich lattices.

Occurrence and synthesis: There is no widely reported synthesis of NdH2O93 as a defined solid; it is more likely to appear as a theoretical construct or as a representation for a hydration shell in computational studies, especially in simulations of solvation and lattice hydration. Experimental hydrates containing neodymium may include Nd salts with several dozen water molecules loosely associated in the crystal lattice, but not a fixed Nd(H2O)93 stoichiometry.

Properties: If a compound with this stoichiometry existed, its properties would depend on the exact lattice and pressure; it would be highly hygroscopic and could release most of its water upon modest heating. In aqueous solutions, Nd3+ exhibits characteristic f–f transitions, yielding pink coloration; hydration dynamics influence conductivity and ion mobility.

See also: Neodymium, Lanthanide hydration, Aqueous coordination chemistry.