Additions and corrections

On the state of the titanium and zirconium in Ti- or Zr-doped NaAlH₄ hydrogen storage material

Claudia Weidenthaler, André Pommerin, Michael Felderhoff, Borislav Bogdanovi and Ferdi Schüth

Phys. Chem. Chem. Phys., 2003, 5, 5149 (DOI: 10.1039/b309409j). Amendment published 9th August 2005

We realized an error in the discussion of the experimental results, which does not affect our line of arguments but should be corrected to avoid confusion or misinterpretations. Sodium in the NaAlH₄ structure is, of course, coordinated by eight hydrogen atoms while the aluminum ions are coordinated by four hydrogen atoms. The ionic radii of the cations are 1.18 Å for Na⁺ and 0.74 Å for Ti⁴⁺ in eightfold coordination. For Ti²⁺ and Ti³⁺, ionic radii for eightfold coordination are not tabulated. However, the ionic radii of these cations in other coordination, such as 0.86 Å and 0.67 Å in sixfold coordination, are also substantially smaller than those of sodium cations in the respective coordination. Thus, substitution of Na by Ti in any coordination does not lead to an increase of the lattice parameters as we already pointed out in the paper.

The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

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