SR9NI6.64O21 - A NEW MEMBER (N=2) OF THE PEROVSKITE-RELATED A(3N+3)A'NB3+NO9+6N FAMILY

Crystals of a new phase Sr9Ni6.64O21 were grown. This compound is the n = 2 member of the A(3n+3)A(n)'Bn+3O6n+9 series. The composition and the crystal structure have been established from X-ray single crystal diffraction data, The structure contains face-shared chains of NiO6 po lyhedra parallel to the c axis and is related with the hexagonal 2H po lytype perovskite, Sr9Ni6.64O21 crystallizes in the space group R(3) o ver barc$ (No. 167) with a = 9.467(2) Angstrom, c = 35.87(5) Angstrom, V = 2784.(4) Angstrom(3), and Z = 6. A comparison is made between the structure of the title compound and the other members of the series. (C) 1996 Academic Press, Inc.