Barium Hydride (BaH₂): Properties and Chemical Context

Barium Hydride (BaH₂)

Introduction to Barium Hydride

Barium hydride is an inorganic compound composed of the elements barium and hydrogen. It is an example of an ionic hydride, which is relevant to the study of chemical compounds and their properties in introductory chemistry.

• Chemical Formula: BaH2

• Classification: Ionic hydride (saline hydride)

• Appearance: White to gray solid

Preparation of Barium Hydride

• Barium hydride is typically prepared by the direct reaction of elemental barium with hydrogen gas at elevated temperatures.

Chemical Equation:

$\mathrm{Ba(s) + H_2(g) \rightarrow BaH_2(s)}$

Chemical Properties

• Reactivity with Water: Barium hydride reacts vigorously with water to produce barium hydroxide and hydrogen gas.

Chemical Equation:

$\mathrm{BaH_2(s) + 2H_2O(l) \rightarrow Ba(OH)_2(aq) + 2H_2(g)}$

• Thermal Stability: Decomposes upon heating to release hydrogen gas.

Applications and Relevance

• Barium hydride is used as a reducing agent in chemical synthesis and as a source of pure hydrogen gas.

• It serves as an example of the behavior of alkaline earth metal hydrides, which is important in understanding periodic trends and chemical bonding.

Comparison: Alkaline Earth Metal Hydrides

The following table compares barium hydride with other alkaline earth metal hydrides:

Compound	Formula	Type	Reactivity with Water
Beryllium hydride	BeH2	Covalent hydride	Reacts slowly
Magnesium hydride	MgH2	Ionic hydride	Reacts moderately
Calcium hydride	CaH2	Ionic hydride	Reacts vigorously
Barium hydride	BaH2	Ionic hydride	Reacts vigorously

Additional info: The trend in reactivity with water increases down the group in the periodic table for alkaline earth metal hydrides.

Summary

• Barium hydride is an important example of an ionic hydride, illustrating key concepts in chemical bonding, reactivity, and periodic trends.

• Its reactions and properties are relevant to introductory chemistry topics such as chemical compounds, chemical reactions, and the behavior of elements in the periodic table.