Crystal and electronic structures of the new ternary silicide Sc12Co41.8Si30.2

• Sc12Co41.8Si30.2 was prepared from the elements by arc melting under argon and subsequent tempering at 800 ​°C for 350 ​h. Single-crystal X-ray diffraction reveals Sc12Co41.8Si30.2 to crystallize in a new hexagonal structure type: Pearson's symbol (PS) hP168, space group P6/mmm, a ​= ​17.291(1), c ​= ​8.0293(8) Å. The crystal structure is formed of three types of atomic layers along the [001] direction – two flat at z ​= ​0 and z ​= ​0.5 and one corrugated at z ​= ​0.16–0.33 and z ​= ​0.67–0.84, shows a substantial degree of positional and occupational disorder and close structural relationships to a series of hexagonal structures with PS hP164–hP171. Quantum chemical calculations have been performed to analyze the electronic structure and provide deeper insight into the structure-property relationships. The quantum chemical calculation indicates that the material features both two-center, two-electron localized bonding and multi-center multi-electron delocalized bonding.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Crystal structure

Electronic structure

Silicides

Scandium

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