Search results
Results from the WOW.Com Content Network
Crystalline boron is a hard, black material with a melting point of above 2000 °C. Crystalline boron is chemically inert and resistant to attack by boiling hydrofluoric or hydrochloric acid . When finely divided, it is attacked slowly by hot concentrated hydrogen peroxide , hot concentrated nitric acid , hot sulfuric acid or hot mixture of ...
This is a list of the various reported boiling points for the elements, with recommended values to be used elsewhere on Wikipedia. For broader coverage of this topic, see Boiling point . Boiling points, Master List format
The borides can be classified loosely as boron rich or metal rich, for example the compound YB 66 at one extreme through to Nd 2 Fe 14 B at the other. The generally accepted definition is that if the ratio of boron atoms to metal atoms is 4:1 or more, the compound is boron rich; if it is less, then it is metal rich.
A given pure compound has only one normal boiling point, if any, and a compound's normal boiling point and melting point can serve as characteristic physical properties for that compound, listed in reference books. The higher a compound's normal boiling point, the less volatile that compound is overall, and conversely, the lower a compound's ...
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Pages for logged out editors learn more
Boric acid in equilibrium with its conjugate base the borate ion is widely used (in the concentration range 50–100 ppm boron equivalents) as a primary or adjunct pH buffer system in swimming pools. Boric acid is a weak acid, with p K a (the pH at which buffering is strongest because the free acid and borate ion are in equal concentrations) of ...
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 boron atom in BH 3 has 6 valence electrons. Consequently, it is a strong Lewis acid and reacts with any Lewis base ('L' in equation below) to form an adduct: [8] BH 3 + L → L—BH 3. in which the base donates its lone pair, forming a dative covalent bond. Such compounds are thermodynamically stable, but may be easily oxidised in air.