The compounds K3SbSe3, Rb3SbSe3 and Cs3SbSe3 were synthesized by heating mi
xtures of Sb2O3 and an alkali-carbonate in a stream of hydrogen saturated b
y selenium in a temperature range between 750 degrees C and 800 degrees C.
The compounds crystallize isostructural with Na3AsS3. A comparison of atomi
c distances and bond angles with those of the isostructural arsenic and bis
muth compounds shows the effect of lone pairs.