BREAKING UP CHAINS - THE NITRIDOCUPRATES(I) BA[CUN] BA-16[(CUN)(8)][CU2N3][CU3N4] AND CA4BA[CUN2](2)

The three title compounds were prepared from copper or copper(I) oxide and alkaline earth metals in sodium fluxes under medium nitrogen pres sures and structurally characterized. Ba[CuN] crystallizes monoclinic in C 2/c (No. 15), with Z=12, a=14.462(2) Angstrom, b=5.5700(8) Angstr om, c=9.478(1) Angstrom, beta=102.960(2)degrees. The structure contain s infinite chains (1)(infinity)[CuN2/22-], which are kinked alternatel y at the first and then the second nitrogen atom. Ba-16[(CuN)(8)][Cu2N 3][Cu3N4] crystallizes monoclinic in P2(1)/c (No. 14), with Z=1, a=9.5 611(4) Angstrom, b=7.2731(2) Angstrom, c=13.5225(5) Angstrom, beta=93. 115(2)degrees. It is build from infinite helical chains (1)(infinity)[ CuN2/22-] separated by discrete linear [Cu2N3](7-) and Z-shaped [Cu3N4 ](9-) ions. Ca4Ba[CuN2](2) crystallizes tetragonal in P 4/ncc (No. 130 ), with Z=4, a=8.2366(4) Angstrom, c=12.5731(6) Angstrom. In this comp ound the nitridocuprate ions are broken down to isolated linear units [CuN2](5-). (C) 1998 Elsevier Science S.A. All rights reserved.