What is Barium Iodide Formula Structure Preparation and Uses
An Introduction To Barium Iodide
Barium is a group 2 element and Iodine is a group 17 element. This means Barium (Ba) is metal and Iodine is a halogen. Metals and halogens react to form metal halide compounds called salts like Barium Iodide. The chemical formula of Barium Iodide is BaI2. Studying different metal halide compounds helps us in understanding the nature of these two types of element. This is not the only fact that makes Barium iodide interesting. Iodide compounds are important in the field of medicine and also for the manufacture of many organic compounds.
Barium Iodide Structure and Barium Iodide Formula
As mentioned earlier the barium iodide formula is BaI2 r. It exists in two forms-a dihydrate form and an anhydrous form. The dihydrate form of barium iodide is when each barium iodide molecule is observed to be attached to the other 2 water molecules. The chemical formula of dihydrate barium iodide is written as BaI2.2H2O. Anhydrous barium iodide will not have any water molecule attached to itself. We can easily obtain anhydrous barium iodide from dihydrate barium iodide by heating the latter and letting the water molecules evaporate. They are crystalline solids.
The Lewis structure of BaI2 is
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The nature of the bond is ionic.
Structure of Anhydrous Barium Iodide
The anhydrous barium iodide appears as a white odorless powder. Anhydrous barium iodide can exist in 2 different cell structures: A PbCl2 structure and a Fe2P type structure. Pbcl2 is an orthorhombic structure with trigonal prismatic coordination and a sawtooth lattice. In the case of barium iodide barium will be in the middle and iodine on both the sides respectively
Fe2P is a hexagonal structure with a triangular lattice along with a phosphorus atom in the center. In the case of barium iodide, barium will be in the middle.
Chemical Properties of Barium Iodide
Chemical properties of barium iodide can vary slightly between anhydrous barium iodide and dihydrate barium iodide. This is due to the presence of water molecules attached to the barium iodide molecules. This makes the molecule soluble in water, ethanol, and acetone. However in the case of anhydrous barium iodide, although stable salt, it is sensitive to air, light, and moisture. It is also hygroscopic; meaning it will readily absorb water to crystalize into the dihydrate form of barium iodide. Both are sensitive to oxides and are toxic for consumption. As they are metal halide compounds so they are also ionic in nature.
Some Important Reactions Involving Barium Iodide
Barium iodide can be made by the reaction of barium and iodine molecules as metals and halogens are highly reactive. Since iodine is lower in the 17th group, we need to provide heat for the reaction to take place.
Ba + I2 → BaI2
The reaction of potassium iodide with barium nitrate in the presence of water will yield dihydrate barium iodide.
KI(aq) + Ba(NO3)2 (aq) → KNO3 (aq) + BaI2(aq)
This type of reaction is called a double displacement reaction and is reversible.
Because this reaction is done in the presence of water, the formation of barium iodide is followed by water molecules forming ligands of barium iodide, and hence the product which we will get is dihydrate barium hydroxide. Potassium nitrate is water-soluble and hence on heating, we obtain the crystalized anhydrous barium iodide.
The properties and reactions of barium iodide show us why studying this compound is both useful and interesting.
FAQs on Barium Iodide Chemical Properties Structure and Applications
1. What is barium iodide?
Barium iodide is an ionic compound composed of barium and iodine with the chemical formula BaI2. It consists of one Ba2+ ion and two I- ions, forming a neutral salt. Barium iodide is typically a white crystalline solid and is highly soluble in water due to its ionic nature. It is commonly studied in inorganic chemistry and ionic bonding topics.
2. What is the formula for barium iodide?
The chemical formula for barium iodide is BaI2. Barium forms a Ba2+ cation and iodide forms an I- anion. To balance the +2 charge of barium, two iodide ions are required:
- Ba2+
- 2 I-
3. Is barium iodide ionic or covalent?
Barium iodide is an ionic compound because it is formed from a metal (barium) and a nonmetal (iodine). Barium loses two electrons to form Ba2+, and each iodine atom gains one electron to form I-. The electrostatic attraction between these oppositely charged ions creates an ionic lattice structure in solid BaI2.
4. How is barium iodide formed?
Barium iodide is formed by the reaction of barium metal with iodine or by neutralization of barium hydroxide with hydroiodic acid. A common formation reaction is:
Ba(s) + I2(s) → BaI2(s)
It can also be prepared by acid–base reaction:
Ba(OH)2(aq) + 2HI(aq) → BaI2(aq) + 2H2O(l)
Both equations are balanced and produce the ionic salt BaI2.
5. What is the molar mass of barium iodide?
The molar mass of BaI2 is approximately 391.14 g/mol. It is calculated by adding atomic masses:
- Ba = 137.33 g/mol
- I = 126.90 g/mol × 2 = 253.80 g/mol
6. Is barium iodide soluble in water?
Yes, barium iodide is highly soluble in water because it is an ionic salt of a strong acid and strong base. When dissolved, it dissociates completely:
BaI2(s) → Ba2+(aq) + 2I-(aq)
The strong ion–dipole interactions between water molecules and the ions promote solubility, which is consistent with solubility rules for most iodide salts (except Ag+, Pb2+, and Hg22+).
7. What type of bond is present in barium iodide?
Barium iodide contains ionic bonds between Ba2+ and I- ions. The bond forms due to electron transfer from barium (a Group 2 metal) to iodine (a halogen). In the solid state, these ions arrange in a crystalline lattice held together by strong electrostatic forces.
8. What happens when barium iodide reacts with silver nitrate?
When barium iodide reacts with silver nitrate, a yellow precipitate of silver iodide forms. The balanced double displacement reaction is:
BaI2(aq) + 2AgNO3(aq) → 2AgI(s) + Ba(NO3)2(aq)
AgI is insoluble in water and precipitates, while barium nitrate remains in solution. This reaction is commonly used to test for iodide ions.
9. What are the physical properties of barium iodide?
Barium iodide is a white crystalline solid that is highly soluble in water and hygroscopic. Key physical properties include:
- Formula: BaI2
- Molar mass: ~391.14 g/mol
- Appearance: white solid
- Solubility: very soluble in water
10. Is barium iodide acidic, basic, or neutral in solution?
Barium iodide forms a neutral solution in water because it is a salt of a strong base and a strong acid. It is derived from Ba(OH)2 (a strong base) and HI (a strong acid). Since neither Ba2+ nor I- undergoes significant hydrolysis, the resulting aqueous solution is approximately neutral (pH ≈ 7).
