The structural, magnetic, electrical and thermoelectric properties of
heavy rare-earths ternary compounds RNiSb were investigated. Except Yb
-based compound (and nonmagnetic Lu), all compounds are low temperatur
e antiferromagnets. YbNi0.9Sb reflects some mixed valence behaviour. M
agnitude of the resistivity indicates that investigated compounds are
semimetals or high doped semiconductors.