K4Fe4P5O20: a new mixed valence microporous compound with elliptical eight-ring channels.
A new small-pore compound K(4)Fe(4)P(5)O(20) was obtained by conventional solid-state reaction in a closed crucible. The crystal structure is constructed by Fe(4)P(5)O(20) units forming chains along the c axis and elliptical eight-ring channels on the a-b plane in which K cations locate inside. Such structural characteristics seem to be quite similar to those seen in the natrolite family. However, Fe ions in K(4)Fe(4)P(5)O(20) have trigonal-bipyramidal instead of common tetrahedral coordination. Furthermore, our experimental results combined from magnetic susceptibility and (57)Fe Mössbauer spectrum measurements show mixed valence Fe(3+)/Fe(2+) in the titled material. To the best of our knowledge, this is the first example that contains mixed valence iron ions in a so-called natrolite framework.
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Mater, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China. hezz@fjirsm.ac.cn
Zhangzhen
Z
He
Weilong
W
Zhang
Wendan
W
Cheng
Atsushi
A
Okazawa
Norimichi
N
Kojima