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New Ternary Alkaline Earth Metal Cerium(IV) Nitrides: CaCeN 2 and SrCeN 2
Author(s) -
Prots' Yurii,
Niewa Rainer,
Schnelle Walter,
Kniep Rüdiger
Publication year - 2002
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 - 10.1002/1521-3749(200207)628:7<1590::aid-zaac1590>3.0.co;2-f
Subject(s) - chemistry , crystallography , structure type , crystal structure , alkaline earth metal , ternary operation , nitride , metal , programming language , organic chemistry , layer (electronics) , computer science
CaCeN 2 and SrCeN 2 were prepared by reactions of Li 2 CeN 2 with Ca 3 N 2 or Sr 2 N in a nitrogen atmosphere at 1020 K. According to measurements of the magnetic susceptibilities both compounds contain Ce IV . The crystal structures were determined by full‐profile Rietveld refinements of the X‐ray powder diffraction patterns. CaCeN 2 crystallizes in a rocksalt‐type structure with disordered Ca and Ce (space group Fm 3¯ m , a = 499.21(1) pm, R profile = 0.061, R Bragg = 0.034). The low temperature modification of SrCeN 2 crystallizes in the α‐NaFeO 2 type structure (space group R 3¯ m , a = 362.18(4) pm, c = 1795.8(2) pm, R profile = 0.085, R Bragg = 0.031). At elevated temperatures an order‐disorder phase transition leads to HT‐SrCeN 2 (space group Fm 3¯ m , a = 515.01(2) pm, quenched from 1273 K) with a cubic unit cell and complete disorder of Sr and Ce.