... .821, b = 5.52, c = 11.46, relative density 6.68, melting point 1890 °C, boiling point 3800 ° C, thermal expansion coefficient of 10 ... .3 x 10-6 / K; chromium ... lattice for positive and negative density of 6.613 g/cm3, melting point 1895 °C, chromium carbide is gray to acid. Micro ...