title: Li3Cs2M2B3P6O24 (M = Pb, Sr): borophosphates with double six-membered ring of [BP2O8](3.).
abstract: New borophosphates Li3Cs2M2B3P6O24 (M = Pb, Sr) have been synthesized by high-temperature solid-state reactions. The single-crystal X-ray diffraction data reveal their non-centrosymmetric cubic space group P213 and lattice parameters of a = 12.7246(3) Å and 12.687(2) Å and V = 2060.31(8) Å(3) and 2042.3(4) Å(3) for Li3Cs2Pb2B3P6O24 and Li3Cs2Sr2B3P6O24, respectively. They are three-dimensional (3D) [BP2O8](3-)∞ anionic frameworks formed by a new double six-membered ring building unit consisting of BO4 and PO4 units joined alternately. Interestingly, such a double six-membered ring is regarded as the structural variation of the 12-membered ring in the known KSrBP2O8, fusing at the BO4 tetrahedron induced by the coexistence of the Li(+) and Cs(+) cations with their large size difference. The title compounds show weak SHG intensity and exhibit photoluminescence emissions at 410 nm for Li3Cs2Pb2B3P6O24 and 440 nm for Li3Cs2Sr2B3P6O24.
authors.affiliation: Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China. chenl@fjirsm.ac.cn and University of Chinese Academy of Sciences, Beijing 100039, People's Republic of China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China. chenl@fjirsm.ac.cn.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Li
authors.affiliation: Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China. chenl@fjirsm.ac.cn and University of Chinese Academy of Sciences, Beijing 100039, People's Republic of China.
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Liu
authors.affiliation: Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China. chenl@fjirsm.ac.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Chen