Use of Long-Spacing Alcohols and Alkanes for Calibration of Long Spacings from Layer Silicates, Particularly Clay Minerals

Lattice spacings of layer silicates, particularly clay minerals, may exceed 20 A. The errors in measuring lattice spacings increase rapidly for spacings greater than about 10 A and diffraction angles 20 tess than about 10 ~ Long-chain organic compounds, such as normal alcohols, ClcC2o, and normal alkancs (paraffins), Cz6-C3o, provide useful calibrations for lattice spacings in the range 10-50 A. The basal spacings of the calibrating substances are determined from their higher order reflections in the angu- lar range where reflections from quartz and silicon are used as standards. INTRODU(.qI'ION