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Synthesis and Structure Determination of AgScP 2 Se 6 , AgErP 2 Se 6 and AgTmP 2 Se 6
Author(s) -
Pfitzner Arno,
Seidlmayer Stefan
Publication year - 2009
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200900004
Subject(s) - crystallography , crystal twinning , octahedron , crystal structure , stoichiometry , ampoule , structure type , lattice constant , materials science , selenium , space group , crystal (programming language) , x ray crystallography , chemistry , diffraction , physics , metallurgy , microstructure , optics , composite material , programming language , computer science
AgScP 2 Se 6 , AgErP 2 Se 6 and AgTmP 2 Se 6 were obtained by high temperature reaction of stoichiometric amounts of the elements in evacuated silica ampoules. They crystallize in the space group P $/bar{3}$ 1 c , Z = 2 with the lattice constants a = 6.463(1) Å, c = 13.349(1) Å (AgScP 2 Se 6 ), a = 6.578(1) Å, c = 13.410(2) Å (AgErP 2 Se 6 ), and a = 6.567(1) Å, c = 13.422(1) Å (AgTmP 2 Se 6 ). The crystal structures of AgScP 2 Se 6 and AgErP 2 Se 6 were refined from merohedrally twinned crystals. No twinning was observed for AgTmP 2 Se 6 . The crystal structures are isotypic and can be described as a variant of the CdI 2 structure type. Thus, selenium atoms are hexagonally close packed. The octahedral voids of every second layer are occupied by Ag, M 3+ ( M = Sc, Er, Tm), and P 2 dumbbells in an ordered fashion. The crystal structures are isotypic to AgScP 2 S 6 and AgInP 2 S 6 .