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Physical & Chemical properties

Melting point / freezing point

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Description of key information

Melting at about  420°C (at 4.8 bar). 
Sublimation starts at about 360°C

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
420 °C

Additional information

Melting of the metastable hexagonal modifcation ( (see remark CSR 1.1.) can only be observed by quick heating, due to the sublimation corresponding with vapour pressure of 3600 mm Hg and the transformation into the orthorhombic modification having a melting point of about 560°C at about 437mmHG (O modification), or 580°C at 555mm Hg (O`modification)