Dielectric and structural properties of iron- and sodium-fumarates
Abstract The behaviour of dielectric parameters such as the relative dielectric constant (ε''), the relative loss factor (ε'') and the ac conductivity of well known pharmaceutical materials Fe(II)-fumarate and Na-fumarate were studied as a function of temperature (in the range from 303K to 483 K) and frequency (in the range from 0.1 Hz to 100 kHz). The values of the conductivity are in the range of 10−5 Ω−1m−1 to 10−9 Ω−1m−1 for Fe(II)-fumarate and 10−6 Ω−1m−1 to 10−11 Ω−1m−1 for Na-fumarate. The conductivity of both materials increases with the increase in temperature and frequency. It was found that both ε' and ε'' decrease with increasing frequency and increase with increasing temperature for both materials. The highest changes are in the low frequency range. The obtained values of the dielectric parameters and conductivity suggest that these materials are dielectric with similar structure, most probably polymeric, with the mechanism of ionic conductivity.