X-ray photoelectron diffraction studies of lepidolite

Abstract

X-ray photoelectron diffraction data for three cleavage surfaces from a crystal of a Norwegian lepidolite containing 2·3% Rb and 3% Mn are reported and interpreted. Rubidium is shown to occupy anhydrous interlayer sites equivalent to those of potassium, and to be distributed uniformly throughout the crystals. Cleavage occurs in Mn-rich regions in which the manganese(II) is located in octahedral sites essentially equivalent to those of lithium. The octahedral Al sites can readily be distinguished from the Li,Mn sites and it is concluded that Al occupies predominantly M(2), cis sites while Li and Mn(II) prefer M(1), trans sites. Photoelectron diffraction data also indicate that 40 ± 5% of the Al is tetrahedrally coordinated, compared with a figure of ∼34% deduced independently from a surface analysis.