A single-crystalline cubic boron nitride(c-BN)(111) surface has been studied by atomic force microscopy with simultaneous measurements of normal atomic force (constant height mode and constant force mode) and lateral (friction) force in air. On the friction force mode the different two domains observed can be attributed to the termination of the surface; boron (Aside) or nitrogen (Bside). 2.6 Å periodicity corresponding to the1×1surface unit cellasofc-BN(111)(as=a0/&sqrt2;=2.56 Å,wherea0is the lattice constant, 3.62 Å) has been observed also on the friction force mode, which is in agreement with our low-energy electron diffraction measurement. ©1998 American Institute of Physics.