PKU-5: an aluminoborate with novel octahedral framework topology.
A new anhydrous aluminoborate Al4B6O15 (PKU-5) has been synthesized in a boric acid flux in a closed system at 350 degrees C. PKU-5, which crystallizes in the space group R3 with the lattice constants a=11.43398(9) and c=6.48307(5) A, consists of Al octahedra and triangularly coordinated boron. The Al octahedron adopts the (10,3)-a network, in which each octahedron shares three edges with the neighboring octahedra forming ten-membered-ring channels. The octahedral backbone in PKU-5 can be considered as a primary octahedral framework topology and, setting out from the structures of the aluminoborates (PKU-1 and PKU-5), we propose construction rules for the octahedral frameworks. There are two types of connections for edge-sharing octahedra in porous frameworks, trans and cis type, by which various microporous octahedral frameworks of different topologies can be constructed. The borate groups share oxygens with the Al octahedral frameworks forming two kinds of three-membered-ring units consisting of two octahedra and one triangle (2Al+B) and one octahedron and two triangles (Al+2B), respectively.
State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
Jing
J
Ju
Tao
T
Yang
Guobao
G
Li
Fuhui
F
Liao
Yingxia
Y
Wang
Liping
L
You
Jianhua
J
Lin
D017607:Aluminum Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D001881:Borates / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D014961:X-Ray Diffraction
D017607:Aluminum Compounds; D001881:Borates