title: Hydrothermal synthesis, crystal structure, and solid-state NMR spectroscopy of a new indium silicate: K2In(OH)(Si4O10).
abstract: A new indium(III) silicate, K(2)In(OH)(Si(4)O(10)), has been synthesized by a high-temperature, high-pressure hydrothermal method. It crystallizes in the monoclinic space group P2(1)/m (No. 11) with a = 11.410(1) A, b = 8.373(1) A, c = 11.611(1) A, beta = 112.201(2) degrees, and Z = 4. The structure, which is analogous to that of K(2)CuSi(4)O(10), consists of unbranched vierer 4-fold chains of corner-sharing SiO(4) tetrahedra running along the b axis linked together via corner sharing by chains of trans-corner-sharing InO(4)(OH)(2) octahedra to form a 3-D framework which delimits 8-ring and 6-ring channels to accommodate K(+) cations. The presence of hydroxyl groups is confirmed by IR spectroscopy. The (29)Si MAS NMR exhibits four resonances at -88.6, -90.1, -97.4, and -98.2 ppm corresponding to four distinct crystallographic Si sites. A (1)H --> (29)Si CP/MAS NMR experiment was performed to assign the four resonances.
authors.affiliation: Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 300, R.O.C.
authors.forename: Ling-I
authors.initials: LI
authors.lastname: Hung
authors.forename: Sue-Lein
authors.initials: SL
authors.lastname: Wang
authors.forename: Hsien-Ming
authors.initials: HM
authors.lastname: Kao
authors.forename: Kwang-Hwa
authors.initials: KH
authors.lastname: Lii