Intermediate Topic 618 of 1102 Inorganic Chemistry
Hydrides
Binary hydrogen compounds classified as ionic, covalent or metallic.
In-depth explanation of Hydrides
A hydride is a compound of hydrogen with a less electronegative element, and hydrides are classified by bonding. Ionic or saline hydrides, formed by the alkali metals and heavier alkaline earth metals, contain the hydride ion H- and react with water to release hydrogen. Covalent hydrides such as CH4, NH3, H2O and HF involve shared electron pairs, and their properties follow from the electronegativity and shape of the central atom. Metallic or interstitial hydrides, such as PdH, form when hydrogen occupies gaps in a metal lattice and are often non-stoichiometric. Complex hydrides such as LiAlH4 are common reducing agents in organic synthesis.
Going deeper: Hydrides
Key ideas: Three classes: ionic or saline (NaH, CaH2, contain H-minus, react with water to give H2), covalent or molecular (CH4, NH3, H2O, B2H6), and metallic or interstitial (PdH, TiH2, nonstoichiometric). Classify by electronegativity difference of the partner element. Ionic hydrides are powerful reducing agents and drying agents; LiAlH4 and NaBH4 are complex hydrides used in organic reduction.
Common mistakes and connections: Students assume all hydrides are acidic or all release H2 on heating. Ionic hydrides act as bases, since H-minus takes a proton from water: NaH + H2O gives NaOH + H2. Covalent hydride acidity grows down a group (HF weak, HI strong) because bond length increases. Connects to periodic trends and hydrogen storage.
Visualization of Hydrides
Electronegativity from H to F: hydrogen (2.2) forms ionic hydrides with less electronegative metals and covalent hydrides with the more electronegative nonmetals. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Lithium hydride reacts with water: LiH + H2O giving LiOH + H2.
Frequently asked questions about Hydrides
What is Hydrides?
Binary hydrogen compounds classified as ionic, covalent or metallic.
Is Hydrides a beginner, intermediate or advanced topic?
Hydrides is a intermediate topic in Inorganic Chemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Hydrides?
Study these earlier topics in Inorganic Chemistry first: Hydrogen, Isotopes of Hydrogen.
What comes after Hydrides?
The next topics in Inorganic Chemistry are Water Chemistry and Heavy Water.
Can I practise Hydrides with quizzes?
Yes. The interactive lesson includes a self-check question on Hydrides, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Hydrides fits in Inorganic Chemistry
Hydrides is topic 3 of 113 in Inorganic Chemistry.