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Despite the high morbidity and mortality rates that resulted from the epidemic, the Spanish flu began to fade from public awareness over the decades until the arrival of news about bird flu and other pandemics in the 1990s and 2000s. [320] [321] This has led some historians to label the Spanish flu a "forgotten pandemic". [177]
This is an accepted version of this page This is the latest accepted revision, reviewed on 31 December 2024. This article is about the chemical element. For other uses, see Iodine (disambiguation). Chemical element with atomic number 53 (I) Iodine, 53 I Iodine Pronunciation / ˈ aɪ ə d aɪ n, - d ɪ n, - d iː n / (EYE -ə-dyne, -din, -deen) Appearance lustrous metallic gray solid ...
Thermally, FEP stands out from PTFE and PFA by having a melting point of 260 °C (500 °F), around 40°C lower than PFA and lower again than PTFE. [5] Electrically, PTFE, FEP and PFA have identical dielectric constants, but FEP's dielectric strength is only surpassed by PFA.
The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C.
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa.
These iodine compounds are hypervalent because the iodine atom formally contains in its valence shell more than the 8 electrons required for the octet rule. Hypervalent iodine oxyanions are known for oxidation states +1, +3, +5, and +7; organic analogues of these moieties are known for each oxidation state except +7.
There is also an oral capsule that contains the oil, equivalent to 190 mg iodine. [18] [19] Iodized poppyseed oil (Lipiodol) given orally or intermuscularly produces a long-lasting store of iodine in the body, allowing very infrequent dosing. Iodized oil is a cost-effective way of combating iodine deficiency.
Trifluoroiodomethane contains carbon, fluorine, and iodine atoms. Although iodine is several hundred times more efficient at destroying stratospheric ozone than chlorine, experiments have shown that because the weak C-I bond breaks easily under the influence of water (owing to the electron-attracting fluorine atoms), trifluoroiodomethane has an ozone depleting potential less than one ...