Properties: Pink or mauve crystal belonging to monoclinic system, density: 1.924G/cm3, melting point: 86° C, stable under room temperature. It turns blue when heated and turns red in the moist air by cooling. Freely soluble in water, alcohol, aether, acetone and glycerin. It changes into anhydride (blue power) when the crystal water is lost.
Application: Used in producing barometrograph, gravimeter in instruments manufacturing industries, paint drier in coating industry, gas defense mask in national defence industry, sympathetic ink, cobalt chloride test paper, allochroic silicagel and nitrogen absorbent. Collocated the feedstuff in stockbreeding,
| Assay(Co) | 24%min |
| Fe | 0.001%max |
| Ni | 0.001%max |
| Zn | 0.001%max |
| Ca | 0.001%max |
| Cu | 0.001%max |
| Mn | 0.001%max |
| Mg | 0.001%max |
| Na | 0.001%max |
| Pb | 0.001%max |
| SO4 | 0.02%max |
| NO3 | 0.01%max |
| Water insoluble matter | 0.01%max |