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Synthesis and Crystal Structure of BaLaSi 2 H 0.80
Author(s) -
Werwein Anton,
Kohlmann Holger
Publication year - 2020
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000152
Subject(s) - hydride , crystallography , neutron diffraction , crystal structure , intermetallic , antibonding molecular orbital , hydrogen , ionic bonding , chemistry , interstitial defect , zintl phase , deuterium , ion , materials science , atomic physics , doping , atomic orbital , physics , optoelectronics , organic chemistry , alloy , quantum mechanics , electron
The polyanionic compound BaLaSi 2 featuring cis‐trans silicon chains takes up hydrogen to form a hydride BaLaSi 2 H 0.80 . The crystal structure of the parent intermetallic compound is largely retained upon hydrogenation with the same space group type, a unit cell volume increase of 3.29 % and very similar atomic positions in the hydride. Hydrogen could be located in the crystal structure by neutron diffraction on the deuteride. Deuterium atoms occupy a tetrahedral Ba 3 La interstitial with 40.6(2) % occupation ( Cmcm, a = 464.43(4) pm, b = 1526.7(1) pm, c = 676.30(6) pm). BaLaSi 2 H 0.80 is thus an interstitial Zintl phase hydride like LaSiH 1– x , but unlike BaSiH 2– x does not feature any covalent Si–H bonds. Si–Si distances within the polyanion increase upon hydrogenation from 240.1(6) and 242.9(5) pm to 244.7(2) pm and 245.5(2) pm. This is probably due to oxidation of the polyanion by hydrogen, which leads to the formation of hydride ions and the depopulation of the polyanion's antibonding π* states. Interatomic Ba–D [260.9(4) pm, 295.7(5) pm] and La–D distances [241.2(7) pm] are in the typical range of ionic hydrides.