The crystal structure and conductivity of pyrochlore-like Ho-2(Ti2-xHox)O7-x/2 (x=0, 0.01, 0.02, 0.096) ceramics are studied by X-ray diffraction and impedance spectroscopy as a function of temperature and oxygen partial pressure in the temperature range 700-1000 degrees C. According to the Rietveld refinement data the fraction of cation anti-site pairs in Ho-2(Ti1.904Ho0.096)O-6.952 sintered at 1400 and 1600 degrees C is 1.5% and 4.3% respectively. Heat treatment of Ho-2(Ti1.904Ho0.096)O-6.952 between 1400 and 1600 degrees C was shown to lead to the formation of pyrochlore-like solid solutions with pure oxide ion conductivities of about 4 x 10(-4) and 1.5 x 10(-3) S/cm at 800 degrees C, respectively. The ionic transport number is similar to 1 at 800 degrees C and Po-2 > 10(-5) Pa. The electrolyte domain was observed for a wide range of oxygen partial pressures (10(-5) Pa > Po-2 > 10(5) Pa), which turns the Ho-2(Ti1.904Ho0.096)O-6.952 ceramic into a typical member of the LANTIOX family, with good oxide ion conductivity. (C) 2010 Elsevier B.V. All rights reserved.