Hartite from Bilina

Charles University, Faculty of Science, Prague, Czech Republic

In the Bilina Mine (Czech Republic), a very chemically pure material corresponding to hartite was found as a product of distillation into the pelosiderite nodule during coalification of a lignite seam in the Miocene or later. The amount of the material available allowed characterizing this natural mineral equivalent of the hydrocarbon (+)-phyllocladane [16alpha (H)-phyllocladane] thoroughly. Elementary analysis of hartite from Bilina gave C = 87.45 wt% and H = 12.55 wt%, which corresponds to the formula C ₂₀ H ₃₄ . The IR spectrum demonstrated the presence of gem-dimethyl groups (doublet delta _s CH ₃ at 1369 and 1383 cm (super -1) ). Other bands indicated the presence of methyl and methylene groups. NMR studies showed that the hydrocarbon (hartite) molecule contains four CH ₃ groups, nine CH ₂ groups, four CH groups, and three quaternary carbon atoms. The sample exhibits a well-defined melting point between 71 and 71.5 degrees C. Measurements of optical rotation gave [alpha ] _D = +24.2 degrees (CHCl ₃ , c = 0.7). Lattice parameters from single-crystal study measured at 293(2) K were a = 11.407 (1), b = 20.952 (2), c = 7.4060 (8) Aa, alpha = 93.941 (9) degrees , beta = 100.750 (8) degrees , and gamma = 80.499 (9) degrees . The crystal system is triclinic with space group Pl, Z = 4, V = 1713.8 (3) Aa ³ . Densities are D _m = 1.04 g/cm ³ and D _x = 1.064 g/cm ³ , respectively. Isotopic composition of C in hartite from Bilina gave delta ¹³ C (sub (PDB)) = -24.4(1) per mil, a common value for coal and organic sedimentary material derived from higher plants.

This record provided courtesy of AGI/GeoRef.