CW and pulsed ENDOR was used to probe the electron nuclear superhyperfine interactions between V4+ ions and distant Sri nuclei in vanadium doped tin oxide (V/SnO2). Whilst interactions with two sets of nearest neighbour Sri nuclei (with a V-Sn distance of 3.185 and 3.708 Angstrom respectively) are observed by EPR, superhyperfine couplings to two remote sets of tins (with a V-Sn distance of 6.370 and similar to7.42 Angstrom) are detected by ENDOR. The interaction was found to be largely isotropic and largest along the crystal c axis. Small differences in the remote tin environments were also detected by ENDOR. (C) 2004 Elsevier B.V. All rights reserved.