Hydrides are hydrogen compounds with fewer electronegative components. When hydrogen reacts with another element, the resulting product is known as a hydride. If we look attentively at the periodic chart, we can see that hydrides do not form from VA group elements, which is known as the hydride gap.
Except for noble gases, the hydrogen molecule normally combines with numerous other elements to generate hydrides. However, the characteristics of the elements can change based on the sort of intermolecular force that exists between them, their molecular weights, temperature, and other circumstances.
Hydrides are classified into three categories. The categories are determined by the elements with which the hydrogen makes bonds or simply by chemical bonding. Ionic (saline), covalent, and metallic (interstitial) hydrides are the three kinds of hydrides.
Dihydrogen reacts with a variety of elements to generate binary compounds known as hydrides. In layman’s terms, the hydride is the anion of hydrogen. It is a chemical molecule with hydrogen atoms that have nucleophilic, basic, or reducing characteristics. In a hydride, the hydrogen usually has an oxidation number of one.
Ionic hydrides
The ionic hydrides are the first sort of categorization. Ionic hydrides are also known as pseudohalides and saline hydrides. Ionic hydrides are created when alkali metals and S block elements react with hydrogen atoms, resulting in the formation of electrovalent compounds. These are the elements with the highest activity levels in the periodic table. They exhibit differing properties in the liquid and solid states.
Ionic hydrides are non-volatile, non-conducting, and crystalline in solid form. In the liquid form, ionic hydrides are excellent conductors of electricity. Hydrogen gas is also created at the anode during electrolysis.
Ionic hydrides include sodium hydride (NaH), potassium hydride (KH), calcium hydride (CaH2), and others. This category includes all alkali metal hydrides. (These contain the negatively charged (H–) ion hydrogen.)
Covalent hydrides
These hydrides are generated when hydrogen interacts with other electronegative elements such as Si, C, and so on.
Covalent hydrides are compounds generated when hydrogen reacts with non-metals in general. The chemicals share a covalent link and can be volatile or non-volatile. Covalent hydrides are both liquids and gases.
Covalent hydrides include boron hydrides, nitrogen hydrides, silicone hydrides (which is saline), and others.
Metallic Hydrides
A metal hydride is a hydrogen compound that establishes a bond with another metal element. The link is generally covalent, however, hydrides can also be produced using ionic bonds. These are often generated by transition metals and are non-stoichiometric, hard, and have high melting and boiling temperatures. Interstitial hydrides are another name for metal hydrides.
One intriguing and distinct feature of these hydrides is that they can be nonstoichiometric, which means that the proportion of H atoms to metals is not set. The composition of nonstoichiometric substances varies. The premise and foundation for this are that in metal and hydrogen bonding, there is a crystal lattice that H atoms can and may fill in between. When a hydrogen molecule combines with the d- and f-block components, these are formed. Groups 7, 8, and 9 metals do not create hydrides. They conduct heat and electricity, although not as well as their parent metals.
Magnesium hydride, aluminium hydride, cadmium hydride, etc., are examples of this category.
Binary Hydrides
In addition to all of these forms of hydrides, binary hydrides constitute a subcategory of hydrides.
Binary hydrides are a kind of chemical in which one element is linked to hydrogen, with hydrogen acting as the more electronegative species. Only in exceptional conditions do free hydride anions occur. Most hydride compounds, on the other hand, have hydrogen centers with a hydridic property.
Binary hydrides include barium hydride, aluminum hydride, cesium hydride, calcium hydride, lithium hydrides, and others.
Hydrides of various sorts have a wide range of uses in chemistry. Some of these uses are listed below.
Ionic hydrides are sometimes known as saline hydrides. The ionic hydrides' chemical characteristics are as follows. These hydrides have a strong crystalline structure and frequently appear white. Ionic hydrides have larger densities because they are stable. These hydrides also have higher boiling and melting points than other hydrides. Ionic hydrides generate hydrogen gas and are excellent electrical conductors.
The following are the qualities related to covalent hydrides. These hydrides feature distinct covalent molecules as well as weak intermolecular interactions. Covalent hydrides, like non-metallic compounds, are poor electrical conductors. The boiling and melting points of covalent hydrides are also low. In the periodic table, these hydrides are more acidic. Covalent hydrides have both non-volatile and volatile characteristics.
The distinction between hydrogen and hydride is that hydrogen is a free radical, whereas hydride has one proton and one electron. While hydride is a negatively charged ion or anion of hydrogen (H-), it is hydrogen with an additional electron.
