## Abstract

Two new ternary platinum borides, YPt_{x}B_{6-2x} and YbPt_{x}B_{6-2x}, were obtained by argon-arc melting of the elements followed by annealing at 780 °C (750 °C). The structures of these compounds combine the fragments of CaB_{6}- and AuCu_{3}-type structures [space group *Pm3̅m*; *x* = 1.15, *a* = 4.0550(4) Å and *x* = 1.34, *a* = 4.0449(2) Å for YPt_{x}B_{6-2x} and YbPt_{x}B_{6-2x}, respectively; single-crystal X-ray diffraction]. Two possible variants of B/Pt ordering (space group P4/*mmm*) were created via a group-subgroup approach targeting the derived stoichiometry. The architecture of the type-**I** YPt_{x}B_{6-2x} structure model (*a*′ = *a*, *b*′ = *b*, *c*′ = *c*) combines the 4.8^{2} boron nets alternating with the layers of Y and Pt; the type-**II** YPt_{x}B_{6-2x} structure model (*a*′ = 2*a*, *b*′ = 2*b*, *c*′ = *c*) exhibits columns of linked [B_{24}] truncated cubes filled with Y running along the *c* axis. The striking features of both structural models are [B_{4}Pt_{2}] octahedra. The structural similarities with hitherto reported structures (YB_{2}C_{2}, M_{2}Ni_{21}B_{20}, MNi_{21}B_{20}, and ErNiB_{4}) were drawn supporting the verity of these models. A chemical bonding analysis for type-**I** and type-**II** YPt_{x}B_{6-2x} based on electron localization function distribution revealed a two-center interaction forming the 4.8^{2} boron nets for type-**I** YPt_{x}B_{6-2x} and a covalent bonding within [B_{4}Pt_{2}] octahedra as well as a two-center interaction for B-B intraoctahedral bonds for type-**II** YPt_{x}B_{6-2x}. Analysis of Bader charges revealed the cationic character of the yttrium atoms. The interactions for nondistorted areas of the structures agree well with the bonding picture calculated for constituent building structures, YB_{6} and YPt_{3}. Electronic structure calculations predict YPt_{x}B_{6-2x} to be a metal with the density of states of around *N*(*E*_{F}) = 1 states eV^{-1} f.u.^{-1}. The exploration of the Y-Pt-B system in the relevant concentration range elucidated the homogeneity field of YPt_{x}B_{6-2x} (0.90 ≤ *x* ≤ 1.40) and revealed the existence of three more ternary phases at 780 °C: YPt_{2}B (space group *P*6_{2}22), YPt_{3}B (space group *P*4*mm*), and YPt_{5}B_{2} (space group *C*2/*m*).

Originalsprache | Englisch |
---|---|

Seiten (von - bis) | 19164-19177 |

Seitenumfang | 14 |

Fachzeitschrift | Inorganic Chemistry |

Jahrgang | 62 |

Ausgabenummer | 47 |

DOIs | |

Publikationsstatus | Veröffentlicht - 10 Nov. 2023 |

## ÖFOS 2012

- 105113 Kristallographie
- 105116 Mineralogie
- 104003 Anorganische Chemie
- 104017 Physikalische Chemie