Cubic crystal system, white crystalline solid block, flaky granule or powder, easy to deliquescence, with a faint smell of bitter almonds. Relative density 1.596. Melting point 563.7 ℃. Boiling point 1496 ℃. Soluble in water, ammonia, ethanol and methanol. Sodium cyanide, which is easy to crystallize from aqueous solutions below 34 °C, often contains one or two crystal waters. When the temperature is above 37,4 °C, the crystal water will be lost and it will become a strong base and weak acid salt. It is easy to react with acids, and even weak acids can react with them. Metals such as iron, zinc, nickel, copper, cobalt, silver and cadmium are dissolved in sodium cyanide solution to produce the corresponding cyanide. With the participation of oxygen, precious metals such as gold and silver can be dissolved to form complex salts. Poisonous!