Neutron powder diffraction study of Ti{sub 2}(OH){sub 2}OSiO{sub 4}.1.5H{sub 2}

Journal Article · Mon May 31 04:00:00 EDT 1999 · Inorganic Chemistry

DOI:https://doi.org/10.1021/ic980984h· OSTI ID:354370

Pertierra, P; Salvado, M A; Garcia-Granda, S ^[1]; Bortun, A I; Clearfield, A ^[2]

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1. Univ. de Oviedo (Spain). Dept. de Quimica Fisica y Analitica
2. Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry

The proton form of the exchanger Na{sub 2}Ti{sub 2}O{sub 3}(SiO{sub 4}){center_dot}2H{sub 2}O exhibits a high selectivity for Cs{sup +} even in acid solutions. A neutron diffraction study was carried out to locate the position of the exchangeable protons. The structure contains cubane-like Ti{sub 4}O{sub 4} clusters bridged by silicate groups. The acidic proton is located on the cubane oxygens which make them four-coordinate, being bonded to three titaniums and one proton. The unit cell is tetragonal. There are six water molecules per tunnel and two tunnels per unit cell. Thus, the empirical formula is Ti{sub 2}(OH){sub 2}OSiO{sub 4}{center_dot}1.5H{sub 2}O. The water molecules are H-bonded to the framework oxygens and to each other. Although the tunnels are filled with water molecules, framework sites normally occupied by Na{sup +} are empty. The high selectivity for Cs{sup +} apparently stems from the ability to form a thermodynamically stable eight-coordinate complex by replacement of the hydroxyl protons.

• Sponsoring Organization: USDOE Office of Environmental Restoration and Waste Management, Washington, DC (United States)
• OSTI ID: 354370
• Journal Information: Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 11 Vol. 38; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
CESIUM
CRYSTAL STRUCTURE
HYDRATES
INORGANIC ION EXCHANGERS
ION EXCHANGE
RADIOACTIVE WASTE PROCESSING
SILICON OXIDES
TITANIUM OXIDES