Mekhanobr Engineering JSC (Russia):

Zuev V. V., Leading Researcher,  office@mekhanobr.spb.ru

Additional arguments are presented in support of the considered in the article «On the problem about nature of Earth’s inner core and possibilities of the existence of substances harder than diamond» (Gornyi Zhurnal, 2012, No 2, pp. 4–7) composition (Fe_0,9Ni_0,1), structure (bodycentered cubic lattice with elementary cell parameter a₀ = 2.49 Å) and the Earth's inner core. New hypothesis on possible cobalt entry into the Earth's inner core central part as separate phase-homoatomic covalent crystal with CN = 9 and realization of 3d⁵4sp³ hybrid interconnections and 9-valent metal, is formulated and substantiated. The formation conditions (Р = 265 GPa and T ≈ 4000–4500 K), as well as unique energy and physical parameters of Co (IX) phase, significantly exceeding those of Fe(VIII)_0,9Ni(VIII)_0,1 phase, are discussed. The issue of quantitative (evidently, quite insignificant) occurrence of new phase remains open, however, the very presence of Fe-Co-Ni elements triad in hypervalent states in the Earth's inner core seems quite real and natural.

1. Zuev V. V. Gonnyy Zhurnal — Mining Journal, 2012, No. 2, pp. 4–7.

2. Dubrovinsky L., Dubrovinskaia N., Narygina O., Kantor I., Kuznetzov A., Prakapenka V. B., Vitos L., Johansson B., Mikhaylushkin A. S., Simak S. I., Abrikosov I. A. Body-Centered Cubic Iron-Nickel Alloy in Earth’s Core. Science, 2007, Vol. 316, pp. 1880–1883.

3. Zuev V. V. Obogashchenie Rud, 1997, No 1, pp. 30–34.

4. Zuev V. V. Konstitutsiya, svoystva mineralov i stroeniye Zemli (energeticheskiye aspekty) (Constitution, properties of minerals and the structure of the Earth  (energy aspects)), St. Petersburg, Nauka, 2005, 402 p.

5. Pauling L. The nature of the chemical bond. Ithaca-New York, Cornell University Press, 1960. 644 p.

6. Zhang Yonghe. Electronegativities of elements in valence states and their application, Inorg. Chem., 1982, Vol. 21, No. 11, pp. 3886–3889.

7. Voitkevich G. V., Kokin A. V., Miroshnikov A. Ye., Prokhorov V. G. Spravochnik po geokhimii (Reference book on geochemistry), Moscow, Nedra, 1990, 480 p.

8. Shriver D., Atkins P. Neorganicheskaya khimiya (Inorganic chemistry). Moscow, Mir, 2004, 486 p.

9. Gillespie R. Geometriya molekul (Molecular geometry), Moscow, Mir, 1975, 278 p.

10. Povarennykh A. S. Tverdost mineralov (Hardness of minerals), Kiev, 1963, 304 p.

11. Zuev V. V. Energoplotnost, svoystva mineralov i energeticheskoye stroyeniye Zemli (Energetical densities, properties of minerals and the structure of the Earth), St. Petersburg, Nauka, 1995, 128 p.