A number of new quaternary rare-earth pyrochlores Ln 2 BSbO 7 are reported with Ln ¼ Pr, Nd, Eu, Gd or Dy, B ¼ Sc, Ga or In. These compositions extend the range of available rare-earth pyrochlores with diamagnetic B-site cations, especially for early lanthanides (Pr, Nd). Rietveld refinements and Mo ¨ssbauer spectroscopy show that most compounds actually contain a fraction of Sb3þ, e.g. have a composition Ln2 (B 3þ 1Àx Sb 3þ
x Sb 5þ )O 7 . In addition, the rather large size of In 3þ induces partial site exchange of Ln and In in Ln 2 InSbO 7 phases. The cell parameters and interatomic distances are in good agreement with those in corresponding Ln 2 M 4þ 2 O 7 pyrochlores. Magnetic measurements show dominant antiferromagnetic interactions and the absence of magnetic ordering down to 2 K, as expected in the geometrically frustrated lanthanide sublattice in the pyrochlore structure. Strong crystal field effects are present in all compounds excepted gadolinium ones. The europium magnetism (J ¼ 0) is well described by a Van Vleck behaviour leading to a finite constant magnetic susceptibility at low temperature.