TY - JOUR

T1 - Synthesis, crystal structure and temperature-dependent properties of gallogermanate nitrite sodalite |Na8(NO2)2|[GaGeO4]6

AU - Poltz, Irma

AU - Robben, Lars

AU - Buhl, Josef Christian

AU - Gesing, Thorsten M.

N1 - Funding Information: We gratefully acknowledge the Deutsche Forschungsgemeinschaft (DFG) for the financial support in the Heisenberg program (GE1981/3-1 and GE1981/3-2). IP likes to thank the University Bremen for her PhD stipendium. Additionally, we like to thank Peter Nowaczyk (Universität Hannover) for the data provided from his Bachelor thesis and project work.

PY - 2015/2

Y1 - 2015/2

N2 - |Na8(NO2)2|[GaGeO4]6 sodalite was synthesized in a two-step process, starting with the formation of gallogermanate basic-hydro-sodalite under mild hydrothermal conditions (1) followed by hydrothermal treatment in concentrated NaNO2 solution (2). The presence of NO2- in the sodalite framework was verified by FTIR and Raman spectroscopy. Crystal structure refinements were performed in the space group P4¯3n from X-ray powder diffraction data using the Rietveld method. a = 915.28(1) pm, V = 766.8(1) × 10-6 pm3, RB = 1.92%. The nitrogen atoms were refined on the 8e (x, x, x) crystallographic position with occupancy. Temperature-dependent properties were investigated by TG-DTA and in-situ X-ray powder diffraction. Debye-Anharmonicity model fit evaluation of the thermal expansion coefficient and the temperature-dependent cell volume behavior indicate intra-cage nitrite to nitrate oxidation around 850 K, confirmed by ex-situ FTIR spectroscopy. The sodalite framework decomposition follows around 935 K, resulting in the beryllonite-type NaGaGeO4.

AB - |Na8(NO2)2|[GaGeO4]6 sodalite was synthesized in a two-step process, starting with the formation of gallogermanate basic-hydro-sodalite under mild hydrothermal conditions (1) followed by hydrothermal treatment in concentrated NaNO2 solution (2). The presence of NO2- in the sodalite framework was verified by FTIR and Raman spectroscopy. Crystal structure refinements were performed in the space group P4¯3n from X-ray powder diffraction data using the Rietveld method. a = 915.28(1) pm, V = 766.8(1) × 10-6 pm3, RB = 1.92%. The nitrogen atoms were refined on the 8e (x, x, x) crystallographic position with occupancy. Temperature-dependent properties were investigated by TG-DTA and in-situ X-ray powder diffraction. Debye-Anharmonicity model fit evaluation of the thermal expansion coefficient and the temperature-dependent cell volume behavior indicate intra-cage nitrite to nitrate oxidation around 850 K, confirmed by ex-situ FTIR spectroscopy. The sodalite framework decomposition follows around 935 K, resulting in the beryllonite-type NaGaGeO4.

KW - Crystal structure

KW - Inorganic compounds

KW - Microporous materials

KW - Thermal expansion

KW - X-ray diffraction

UR - http://www.scopus.com/inward/record.url?scp=84926178716&partnerID=8YFLogxK

U2 - 10.1016/j.micromeso.2014.10.007

DO - 10.1016/j.micromeso.2014.10.007

M3 - Article

AN - SCOPUS:84926178716

VL - 203

SP - 100

EP - 105

JO - Microporous and Mesoporous Materials

JF - Microporous and Mesoporous Materials

SN - 1387-1811

IS - C

ER -