B

Barium

IUPAC: Barium

Ba Elements CAS 7440-39-3
Quick Reference
Formula / NotationBa
CAS Number7440-39-3
Molecular Weight137.33
Melting Point727.0
Boiling Point1897.0
Density3.51
SolubilityReacts with water
AppearanceSoft, silvery-white metal
Also Known AsBa, barium metal
CategoryElements

What is Barium?

Barium is a soft, silvery alkaline earth metal, atomic number 56. Highly reactive - reacts with water and air. Barium sulfate (BaSO4) is uniquely insoluble and non-toxic - used as a radiopaque contrast agent in X-ray imaging. Most soluble barium compounds are toxic.

Formula & Notation

Ba

IUPAC Name: Barium

Other Names / Synonyms: Ba, barium metal

Properties & Characteristics

Atomic number: 56. Atomic mass: 137.33 g/mol. Period 6, Group 2. Melting point: 727 C. Boiling point: 1897 C. Density: 3.51 g/cm3. Electronegativity: 0.89. Oxidation state: +2. Green flame test. Seven stable isotopes.

Physical Data

PropertyValue
Melting Point727.0
Boiling Point1897.0
Density3.51
Molecular Weight137.33
SolubilityReacts with water
AppearanceSoft, silvery-white metal

Uses & Applications

Barium sulfate (BaSO4): X-ray contrast agent (barium meal/enema). Green colour in fireworks (BaCl2, Ba(NO3)2). Getter in vacuum tubes. Oil well drilling muds (barite). Glass and ceramics. Barium carbonate as rat poison.

Safety Information

Soluble barium compounds (BaCl2, Ba(NO3)2, BaO): highly toxic - cardiac toxin causing hypokalaemia, muscle paralysis. LD50 BaCl2: ~150 mg/kg. BaSO4 (insoluble): non-toxic, safe for medical use. BaO reacts violently with water. Ba(NO3)2: oxidiser and fire hazard.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Barium
Formula Ba
CAS Number 7440-39-3
Molecular Weight 137.33
Category Elements
Synonyms Ba, barium metal

Frequently Asked Questions

Barium is a soft, silvery alkaline earth metal, atomic number 56. Highly reactive - reacts with water and air. Barium sulfate (BaSO4) is uniquely insoluble and non-toxic - used as a radiopaque contrast agent in X-ray imaging. Most soluble barium compounds are toxic.

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