It has been found that high ‐resistivity ingots result from the zone refining of the compound in crucibles. Distribution coefficients of the spectroscopically observed impurities in were found to be 0.1 and smaller. Resistivity and Hall coefficients have been determined for some single ‐crystal specimens cut from the zone ‐melted ingots. Single crystals of have been grown by pulling from the melt. These crystals exhibited low resistivities. The mobility for holes in the crystals has been found to range between 300 and 500 cm2/v ‐sec.