Synthesis, Structure, and Chemical Bonding in CaCoSi

The intermetallic compound CaCoSi was synthesized by solid state synthesis and investigated by means of X‐ray diffraction (both powder and single crystal method): PbClF type structure, P4/nmm (No.129): a = 3.977(1) Å, c = 7.089(5) Å, R1 = 0.0303, 121 F2, 9 variable parameters. CaCoSi contains isolated [CoSi]2– 2D layers in the ab plane, which are separated by Ca2+ cations along the c direction. The crystal chemistry and chemical bonding of CaCoSi are discussed in terms of LMTO band structure calculation and analyzed using the Electron Localization Function (ELF).