Kristallstrukturen aus CaBe2Ge2‐ und CeMg2Si2‐analogen Blöcken: Die Phosphide LnPt2P2−x (Ln: La, Sm)

Crystal Structures of CaBe2Ge2 and CeMg2Si2 analogous Units: The Phosphides LnPt2P2−x (Ln: La, Sm) Single crystals of LaPt2P1.44 (a = 4.174(1), c = 19.212(5) A) were grown by reaction of vaporous phosphorus with LaPt2 at 1050 °C during two weeks, whereas SmPt2P1.50 (a = 4.131(1), c = 19.086(4) A) was synthesized by heating mixtures of the elements at 900 and 1100 °C (60 h) and annealing at 1050 °C (300 h). Both phosphides were investigated by single crystal X-ray methods. Their crystal structures (I4/mmm; Z = 4) consist of CaBe2Ge2 and CeMg2Si2 analogous units alternating with each other along [001]. The positions of the P1 atoms are occupied incompletely causing the deviation to the 1:2:2 stoichiometry. Another compounds LnPt2P2−x were studied by X-ray powder diffraction resulting in the following lattice constants: a = 4.150(1), c = 19.132(5) A for CePt2P2–x, a = 4.137(1), c = 19.085(4) A for PrPt2P2−x, and a = 4.127(1), c = 19.040(2) A for NdPt2P2−x.

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