Preparation, ionic conductivity, and humidity-sensing property of novel, crystalline microporous germanates, Na[sub 3]HGe[sub 7]O[sub 16][center dot]xH[sub 2]O, x = 0-6. 1
- State Univ. of New Jersey, New Brunswick, NJ (United States)
A crystalline microporous germanate, Na[sub 3]HGe[sub 7]O[sub 16][center dot]6H[sub 2]O, has been hydrothermally synthesized from a Na[sub 2]O-GeO[sub 2]-H[sub 2]O system. This phase undergoes a phase transition to Na[sub 3]HGe[sub 7]O[sub 16][center dot]xH[sub 2]O, x = 0-4 at [approximately]160[degrees]C. Both phases of the sodium germanates have been characterized by powder X-ray diffraction and differential thermal and thermogravimetric analyses. Sodium and proton ionic conductivities in Na[sub 3]HGe[sub 7]O[sub 16][center dot]6H[sub 2]O, Na[sub 3]HGe[sub 7]O[sub 16][center dot]4H[sub 2]O, and dehydrated Na[sub 3]HGe[sub 7]O[sub 16] were studied by an ac impedance technique. In Na[sub 3]HGe[sub 7]O[sub 16][center dot]6H[sub 2]O motion of surface, bulk proton, and Na[sup +] ion respectively dominate the conductivity in different temperature ranges. The conductivity in dehydrated Na[sub 3]HGe[sub 7]O[sub 16] is [approximately]10[sup [minus]8] ([Omega] cm)[sup [minus]1] at 125[degrees]C and [approximately]10[sup [minus]3] ([Omega] cm)[sup [minus]1] at 500[degrees]C with an activation energy E[sub a] = 0.64 eV. Humidity-sensing property of Na[sub 3]HGe[sub 7]O[sub 16][center dot]6H[sub 2]O and Na[sub 3]HGe[sub 7]O[sub 16][center dot]4H[sub 2]O was investigated in the temperature range 50-120[degrees]C. 25 refs., 13 figs., 1 tab.
- OSTI ID:
- 6732423
- Journal Information:
- Chemistry of Materials; (United States), Vol. 4:2; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GERMANATES
IONIC CONDUCTIVITY
HYDROGEN COMPOUNDS
SODIUM COMPOUNDS
ACTIVATION ENERGY
CHEMICAL PREPARATION
DIFFERENTIAL THERMAL ANALYSIS
HUMIDITY
PHASE TRANSFORMATIONS
STOICHIOMETRY
THERMAL GRAVIMETRIC ANALYSIS
ALKALI METAL COMPOUNDS
CHEMICAL ANALYSIS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY
GERMANIUM COMPOUNDS
GRAVIMETRIC ANALYSIS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUANTITATIVE CHEMICAL ANALYSIS
SYNTHESIS
THERMAL ANALYSIS
360606* - Other Materials- Physical Properties- (1992-)