What are the physical properties of molybdenum trioxide?

1, properties: white crystalline powder or yellow white powder, rhombic crystal system crystal. Turns yellow in heat, recovers in cold.

2. Density: Relative density (water =1) : 4.69

3, molecular weight: 143.94

4. Melting point (ºC) : 801

5. Boiling point (ºC, atmospheric pressure) : 1155

6, solubility: slightly soluble in water, easy to dissolve in excess alkali into molybdate, soluble in concentrated nitric acid, hydrochloric acid or concentrated nitric acid and sulfuric acid mixture, soluble in ammonia, hydrofluoric acid, insoluble in general acid.