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The structure of sodium oxide has been determined by X-ray crystallography.Most alkali metal oxides M 2 O (M = Li, Na, K, Rb) crystallise in the antifluorite structure.In this motif the positions of the anions and cations are reversed relative to their positions in CaF 2, with sodium ions tetrahedrally coordinated to 4 oxide ions and oxide cubically coordinated to 8 sodium ions.
There is a strong correlation between higher sodium intake and higher blood pressure. [96] Studies have found that lowering sodium intake by 2 g per day tends to lower systolic blood pressure by about two to four mm Hg. [97] It has been estimated that such a decrease in sodium intake would lead to 9–17% fewer cases of hypertension. [97]
Sodium soaps have a higher melting temperature (and seem "harder") than potassium soaps. [7] Sodium containing mixed oxides are promising catalysts [9] and photocatalysts. [10] Photochemically intercalated sodium ion enhances the photoelectrocatalytic activity of WO 3. [11] Like all the alkali metals, sodium reacts exothermically with water.
The formation reaction is a constant pressure and constant temperature process. Since the pressure of the standard formation reaction is fixed at 1 bar, the standard formation enthalpy or reaction heat is a function of temperature. For tabulation purposes, standard formation enthalpies are all given at a single temperature: 298 K, represented ...
Values are given in terms of temperature necessary to reach the specified pressure. Valid results within the quoted ranges from most equations are included in the table for comparison. A conversion factor is included into the original first coefficients of the equations to provide the pressure in pascals (CR2: 5.006, SMI: -0.875).
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.
Sodium peroxide is an inorganic compound with the formula Na 2 O 2.This yellowish solid is the product of sodium ignited in excess oxygen. [3] It is a strong base. This metal peroxide exists in several hydrates and peroxyhydrates including Na 2 O 2 ·2H 2 O 2 ·4H 2 O, Na 2 O 2 ·2H 2 O, Na 2 O 2 ·2H 2 O 2, and Na 2 O 2 ·8H 2 O. [4] The octahydrate, which is simple to prepare, is white, in ...
The following is a table of some constant-pressure molar heat capacities c P,m of various diatomic gases at standard temperature (25 °C = 298 K), at 500 °C, and at 5000 °C, and the apparent number of degrees of freedom f * estimated by the formula f * = 2c P,m /R − 2: