Nature: colorless crystals or Orthorhombic Department of amorphous white powder. Relative density of 4.50 (15 CentidegreeMelting point 1580 Centidegree. Hardly soluble in water, ethanol and acid. Soluble in hot concentrated sulfuric acid, the dry caking easy. 600 centidegree when the carbon can be reduced to barium sulfide.