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Sodium sulfide is a chemical compound with the formula Na 2 S, or more commonly its hydrate Na 2 S·9H 2 O.Both the anhydrous and the hydrated salts in pure crystalline form are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides and commonly supplied as a crystalline mass, in flake form, or as a fused solid.
Lewis structure of a water molecule. Lewis structures – also called Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDs) – are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.
At temperatures above 360 K, NaSH adopts the NaCl structure, which implies that the HS − behaves as a spherical anion owing to its rapid rotation, leading to equal occupancy of eight equivalent positions. Below 360 K, a rhombohedral structure forms, and the HS − sweeps out a discoidal shape. Below 114 K, the structure becomes monoclinic.
The structure has been examined by Raman spectroscopy and X-ray crystallography. The dithionite dianion has C 2 symmetry, with almost eclipsed with a 16° O-S-S-O torsional angle. In the dihydrated form (Na 2 S 2 O 4 ·2H 2 O), the dithionite anion has gauche 56° O-S-S-O torsional angle. [1]
Structure of anhydrous sodium sulfite. Sodium sulfite can be prepared by treating a solution of sodium hydroxide with sulfur dioxide. When conducted in warm water, Na 2 SO 3 initially precipitates as a white solid. With more SO 2, the solid dissolves to give the disulfite, which crystallizes upon cooling. [2]
In compounds, sodium is usually ionically bonded to water and anions and is viewed as a hard Lewis acid. [25] Two equivalent images of the chemical structure of sodium stearate, a typical soap. Most soaps are sodium salts of fatty acids. Sodium soaps have a higher melting temperature (and seem "harder") than potassium soaps. [24]
The most common Lewis bases are anions. The strength of Lewis basicity correlates with the pK a of the parent acid: acids with high pK a 's give good Lewis bases. As usual, a weaker acid has a stronger conjugate base. Examples of Lewis bases based on the general definition of electron pair donor include: simple anions, such as H − and F −
Lone pairs (shown as pairs of dots) in the Lewis structure of hydroxide. In science, a lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bond [1] and is sometimes called an unshared pair or non-bonding pair. Lone pairs are found in the outermost electron shell of atoms.