title: Ca10Ge16B6O51 and Cd12Ge17B8O58: two types of new 3D frameworks based on BO4 tetrahedra and 1D [Ge4O12]n chains.
abstract: Two new acentric borogermanates, Ca(10)Ge(16)B(6)O(51) (Pba2) and Cd(12)Ge(17)B(8)O(58) (P4), have been successfully synthesized by high-temperature solid-state reactions of CaCO(3) (or CdCO(3)), GeO(2), and H(3)BO(3). Both structures display the same one-dimensional (1D) [Ge(4)O(12)](n) chains composed of GeO(4) tetrahedra and GeO(6) octahedra. In Ca(10)Ge(16)B(6)O(51), neighboring 1D [Ge(4)O(12)](n) chains are condensed into a two-dimensional (2D) [Ge(4)O(10.75)](n) layer via corner sharing, and such layers are further interconnected by "isolated" BO(4) tetrahedra and B(2)O(7) dimers into a three-dimensional (3D) framework, forming 1D tunnels of 5-, 6-, and 7-MRs along the c axis that are occupied by Ca(2+) cations. In Cd(12)Ge(17)B(8)O(58), neighboring 1D [Ge(4)O(12)](n) chains are interconnected into a [Ge(4)O(10.5)](n) open framework via corner sharing with large pores filled by big [Ge(B(2)O(7))(4)](28-) clusters, leading to formation of three types of 1D tunnels of 5-, 6-, and 7-membered rings (MRs) along the c axis which are occupied by the Cd(2+) cations. Both compounds are transparent in the range of 0.3-6.67 μm and exhibit very weak SHG responses.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Xu
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Hu
authors.forename: Fan
authors.initials: F
authors.lastname: Kong
authors.forename: Jian-Han
authors.initials: JH
authors.lastname: Zhang
authors.forename: Jiang-Gao
authors.initials: JG
authors.lastname: Mao