Synthesis, crystal structures, and ion-exchange properties of a novel porous titanosilicate

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Chemistry of Materials

DOI:https://doi.org/10.1021/cm00048a024· OSTI ID:39392

Poojary, D M; Cahill, R A; Clearfield, A ^[1]

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1. Texas A&M Univ., College Station, TX (United States)

A sodium titanosilicate of ideal composition Na{sub 2}Ti{sub 2}O{sub 3}SiO{sub 4}{center_dot}2H{sub 2}O was synthesized hydrothermally in highly alkaline media. Its crystal structure was solved from X-ray powder data by ab initio methods. The compound is tetragonal, a = 7.8082(2), c = 11.9735(4) {angstrom}, space group P4{sub 2}/mcm, Z = 4. The titanium atoms occur in clusters of four grouped about the 4{sub 2} axis and are octahedrally coordinated by oxygen atoms. The silicate groups serve to link the titanium clusters into groups of four arranged in a square of about 7.8 {angstrom} in length. These squares are linked to similar ones in the c direction by sharing corners to form a framework which encloses a tunnel. Half the Na{sup +} ions are situated in the framework coordinated by silicate oxygen atoms and water molecules. The remaining sodiums are present in the cavity, but evidence indicates that some of them are replaced by protons. The composition is then closer to Na{sub 1.64}H{sub 0.36}Ti{sub 2}O{sub 3}SiO{sub 4}{center_dot}1.8H{sub 2}O. The sodium ions within the tunnels are exchangeable. Exhaustive exchange with CsNO{sub 3} yielded a Cs{sup +} phase of composition Na{sub 1.49}Cs{sub 0.2}H{sub 0.31}Ti{sub 2}O{sub 3}SiO{sub 4}{center_dot}H{sub 2}O whose structure was revealed from application of Rietveld methods to X-ray powder data. 19 refs., 7 figs., 5 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 39392
• Journal Information: Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 12 Vol. 6; ISSN 0897-4756; ISSN CMATEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
ION EXCHANGE MATERIALS
POROUS MATERIALS
TITANIUM SILICATES