Removal of Potassium Alters b -Dimension of Muscovite

Abstract

By treatment of muscovite with molten lithium nitrate at 300°C we have been able to remove a large portion of the interlayer potassium and observe a decrease in the apparent b-axis length as a function of potassium content over the range of 8.8 to 0.7 percent potassium. The b-axis length of Silversheen mica (a 2M₁ muscovite) decreases from 9.024 to 8.988 Å as the potassium content decreases from 8.79 to 3.31 percent. The contraction of the b-dimension results in an effective decrease in the size of the ditrigonal opening in the planar surfaces with a consequent increase in the d₀₀₁ upon re-saturation with potassium.