NEUTRON-DIFFRACTION STUDIES OF NETWORK STRUCTURE IN AMORPHOUS PHOSPHORUS

Neutron diffraction studies have been made for three samples of amorph ous phosphorus. The structure factor data have been transformed to giv e the real-space correlation function, d(r). All samples were found to contain a small proportion of hydrogen and corrections were made befo re the data was analysed. The violet form was found to give a typical amorphous pattern which had a sharp main diffraction peak at 1.1 angst rom-1. On heat-treating the sample, this peak increased in intensity b ut the rest of the pattern was unaltered. The red-brown form exhibited some Bragg peaks, but the overall shape of the pattern was similar to that of the violet material. The d(r) function exhibits a sharp peak at 2.21 angstrom corresponding to the PP-bondlength and a second peak at 3.45 angstrom defining a mean bond-angle of 102.6-degrees with a sp read of 4-degrees. At higher values there is a distinct three-peak cha racteristic which is not reproduced in current models based on a three -bonded CRN scheme.