A Series of Lithium Rare Earth Polyphosphates [LiLn(PO₃)₄] (Ln = La, Eu, Gd) and Their Structural, Optical, and Electronic Properties

Abstract

Abstract The structural, optical, and electronic properties of a series of lithium rare earth polyphosphates [LiLn(PO 3 ) 4 ] [Ln = La ( 1 ), Eu ( 2 ), Gd ( 3 )] have been investigated by means of single‐crystal X‐ray diffraction, elemental analyses, and spectroscopic measurements, as well as calculations of energy‐band structures, density of states, and optical response functions by density functional methods. These LiLn(PO 3 ) 4 systems are monoclinic with space group C 2/ c and Z = 4. Their unit‐cell parameters decrease as the ionic radius of Ln 3+ decreases (La 3+ > Eu 3+ > Gd 3+ ). Both (PO 4 ) 3– zig‐zag chains and infinite chains formed by the alternate connection of LnO 8 polyhedra and LiO 4 tetrahedra run parallel to the b ‐axis in the structure. The energy‐band structures, density of states, the chemical bonds, and optical properties have been investigated by density functional methods for some of the title compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)