# Minimum heating temperature for dehydration of Cobalt Chloride

I've been looking on line and have found several sources that state 100°C for a rapid dehydration of cobalt chloride in its various forms. I'm wondering if that's a minimum, or would it be possible to dehydrate it at a much lower temperature, provided ambient humidity is controlled.

The minimum I could find is 110℃(Chemical forums) although not verified

Next is 150℃ from this link. Although, two temperature are written(110℃ and 150℃).

mp 86 °C; loses $\ce{6 H2O}$ at 110 °C

Anhydrous cobalt chloride is blue in color. It can be prepared by dehydration of the hexahydrate either at 150–160 °C in vacuo.

Next is 160-170℃. (Chemiday)

$$\ce{CoCl2•6H2O ->[\Delta] CoCl2 + 6H2O}$$ The thermal decomposition of hexahydrate cobalt(II) chloride to produce cobalt(II) chloride and water. This reaction takes place at a temperature of 160-170°C in a flow dry $\ce{HCl}$.

Next is 200℃. From this paper:

Thermal deaquation of cobalt chloride hexahydrate has been subjected to investigation by numerous authors because it is one of the salts that shows distinct steps in the loss of water of crystallization in the ambient temperature range of 200℃.