The chemical compound that is formed by a hydrogen and any other element is called a hydride.
A hydride is a compound formed by a hydrogen and any other element. When the chemical compound is composed of a hydrogen and a metal , it is a metal hydride . On the other hand, if hydrogen combines with an element that is not a metal, it is called a nonmetal hydride .
Metal hydrides are named through the term "hydride" followed by the preposition "of" and the name of the metal : calcium hydride , lithium hydride , etc. As for its formula, the symbol of the metallic element is first written.
Examples of hydrides
Calcium hydride, in this sense, has the formula CaH2 ( Ca is calcium ), while lithium hydride has the formula LiH (the symbol for lithium is Li ).
The chemical compound called lithium hydride is a colorless crystalline solid, although commercial samples exhibit a grayish hue. Another way to define it is as an inorganic salt composed of hydride anions H- and lithium Li+ cations. Something it shares with the rest of the salt hydrides is a high melting point, in this case 689 degrees Celsius. Since its ions are extremely light, its molecular mass is close to 8 and a density of 780 kilograms per cubic meter, the lowest of any compound in this class.
Lithium hydride has various applications, such as the following:
* in the process carried out to synthesize lithium aluminum hydride, it acts as a precursor ;
* in the generation and storage of hydrogen;
* in nuclear reactors, it is used for shielding and cooling;
* as part of pottery making;
* is a reducing agent.
The notion of hydride is used in the field of chemistry.
The case of lithium and sodium
It is necessary to point out that lithium is the lightest of the cations , within the group of hydrides. Furthermore, lithium hydride has the highest hydrogen content of all hydrides: compared to sodium hydrides, we can say that it exceeds it three times. Regarding hydrogen storage, one of the most frequent uses of this compound, its tendency to decompose usually negatively affects its potential.
On the other hand we have sodium hydride , a chemical compound whose formula is NaH . In the construction of organic molecules through chemical reactions (a process known as organic synthesis ), this hydride is used as a strong base.
One of the main differences between sodium hydride and other non-metals, such as methane, ammonia and borane, it is ionizable, soluble in molten sodium and insoluble in organic solvents. Because of its insolubility, the reactions of this hydride occur on the surface. To generate it, a reaction of liquid sodium and hydrogen must take place. Regarding its density, it exceeds sodium by 40 percent.
Hydrogen, oxidation and hydrides
It is important to note that metal hydrides are the only compounds in which hydrogen has the oxidation number -1 .
In non-metallic hydrides, however, the oxidation number of hydrogen is 1 (positive; that is, +1 ). In these cases, the nonmetal appears with its lowest valence number and, at room temperature, is in a gaseous state.
To name a nonmetal hydride, you must add the ending -ide to the root of the nonmetal and then specify "hydrogen" : hydrogen chloride (chlorine + hydrogen), hydrogen fluoride (fluorine + hydrogen).
It should be noted that, depending on the type of element with which it is combined, the hydrogen in hydrides can form ionic or covalent bonds. By associating with the other element directly, the molecule dissociates and forms the new compound.