Li₅OCl₃ and Li₃OCl: Two Remarkably Different Lithium Oxide Chlorides

Abstract

Abstract Yellow to red, transparent single crystals of the lithium oxide chloride Li 5 OCl 3 were obtained as main product from a solid‐state reaction between Li 3 N and oxygen‐contaminated lithium (covered by a Li[OH] crust) with YbCl 3 and carbon in silica‐jacketed, arc‐welded niobium ampoules originally designed to yield Yb[CN 2 ]. Li 5 OCl 3 adopts the crystal structure of Cs 3 CoCl 5 (≡ Cs 3 Cl[CoCl 4 ]) according to Cl 3 Li[OLi 4 ] with the tetragonal space group I4 / mcm (no. 140) and the cell parameters a = 685.28(3) pm and c = 1093.23(5) pm for Z = 4. Hence, it contains isolated [OLi 4 ] 2+ tetrahedra in a LiCl matrix it thus can be compared with other alkali‐ and alkaline‐earth metal oxide chlorides. Its unconventional color might be due to the fact that small parts of O 2– are substituted with isoelectronic imide anions ([NH] 2– ). Additionally cubic perovskite ‐type Li 3 OCl with corner‐sharing [OLi 6 ] 4+ octahedra according to $\rm^{3}_{\infty}$ {[OLi 6/2 ]Cl} could be obtained during attempts to synthesize Li 5 OCl 3 from Li 2 O and LiCl as colorless powder and its lattice parameter for the space group Pm $\rm^{3}_{\infty}$ m (no. 221) was determined to a = 390.70(4) pm ( Z = 1) by means of X‐ray powder diffraction.