Forelesninger holdt ved Advanced Study Institute of Feldspar - Oslo 1962
Lectures held at Advanced Study Institute of Feldspar - Oslo 1962

A three-dimensional refinement of the low-temperature form of albite, NaAlSi₃O₈, confirms the apparent anisotropy of the sodium atom that was shown in the two-dimensional structure analysis by Ferguson, Traill and Taylor (1958). "Split" sodium half-atoms approximate this anisotropy, and refinement procedes successfully using the half-atom positions of Williams (1961). The final coordinates indicate a 0.35 Å "splitting" for sodium. The mean Al/Si-O bond lengths are: T₁(O), 1.744 Å; T1(m), 1.610 Å; T2(O), 1.616 Å; T2(m), 1.613 Å.