Crystal structure of the R2PbSe4 (RÂ =Â Er and Yb) compounds

The crystal structure of the R2PbSe4 (R = Er and Yb) compounds (space group Pnma, Pearson symbol oP28, a = 1.2541(3) nm, b = 0.40810(8) nm, c = 1.4865(3) nm, R1 = 0.0547 for Er2PbSe4 and a = 1.2501(2) nm, b = 0.40380(8) nm, c = 1.4707(3) nm, R1 = 0.0469 for Yb2PbSe4) was determined by means of X-ray single crystal diffraction. Octahedral surrounding exists for the R atoms. The Pb atoms are surrounded by trigonal prisms with one additional atom.