character |
colorless, odorless, tasteless and nonflammable gas. relative density: 1.88 (liquid, -50.5℃), 2.683 (liquid, -195℃), 5.11(gas, 20℃, air = 1). melting point: -50.5℃ (pressure).-63.8℃sublimation. slightly soluble in water and alcohol. good heat resistance (stable at above 500℃), thermal conductivity and dielectric properties. chemically stable, nonreactive with water, ammonia, sodium hydroxide or hydrochloric acid. nonreactive with dry copper, silver, iron, aluminum, etc. below 300℃ and nonreactive with quartz below 500℃. reactive with metallic sodium at 250℃. |