MYb(BH₄)₄(M= K, Na) from laboratory X-ray powder data

Abstract

Two new borohydrides, potassium ytterbium tetraborohydride, KYb(BH4)4, and sodium ytterbium tetraborohydride, NaYb(BH4)4, have been synthesized via mechanochemical reactions in the solid state. The two compounds are isostructural and both crystallize in the Cmcm space group in the structure reported previously for NaSc(BH4)4 and KY(BH4)4. This crystal structure is composed of isolated homoleptic [Yb(BH4)4](-) anions surrounded by M(+) cations (M = Na, K). The packing of the M(+) cations and [Yb(BH4)4](-) anions is a distorted variant of the hexagonal NiAs structure type, with M(+) forming distorted trigonal prisms, i.e. M6. Each second prism surrounds a [Yb(BH4)4](-) anion, while the [Yb(BH4)4](-) anions are arranged into deformed octahedra around the M(+) cations.

Borohydride as Magnetic Superexchange Pathway in Late Lanthanide Borohydrides

“…Additionally, in case of reactions conducted according to Equation and Equation , KHo(BH 4 ) 4 , NaYb(BH 4 ) 4 , RbTm(BH 4 ) 4 and LiYb(BH 4 ) 4 were obtained as main products, along with LiCl. NaYb(BH 4 ) 4 and KHo(BH 4 ) 4 are isostructural with NaSc(BH 4 ) 4 , KY(BH 4 ) 4 , KYb(BH 4 ) 4 , and NaLn(BH 4 ) 4 (Ln = Ce, Pr, Er, Gd) and adopt the space group Cmcm . Obtained LiYb(BH 4 ) 4 is stable at room temp., whereas no other LiLn(BH 4 ) 4 system was obtained at r.t.…”

“…For (Equation 4) [LiYb(BH 4 ) 4 ] the milling time was 20 min. For further details about synthesis, crystal structures and phase composition as obtained from Rietveld refinement, see references , , …”

Rare Earth Borohydrides—Crystal Structures and Thermal Properties

“…The Na(BH4)6 octahedra form edge-sharing chains along the c-axis, with the chains also being interconnected by egde-sharing Sc(BH4)4 tetrahedra. NaY(BH4)4 [10,40], NaEr(BH4)4 [42], KHo(BH4)4 [32], o-KY(BH4)4 [43], KEr(BH4)4 [44], and KYb(BH4)4 [45] are isostructural to NaSc(BH4)4. KSc(BH4)4 (space group Pnma) contains similar tetrahedral [Sc(BH4)4] − complexes while the coordination number of alkali metal increases further to eight [46].…”

Polymorphism and hydrogen discharge from holmium borohydride, Ho(BH4)3, and KHo(BH4)4

“…similarly to M[Lu(BH 4 ) 4 ], M ¼ Na, K [19]. Reaction (3) results in lower dead mass of halide byproduct (LiCl) and better crystallinity of mixed-metal borohydride product as compared to the immediate reaction in the mixture of RECl 3 and KBH 4 (e.g.…”

“…K[Ho(BH 4 ) 4 ] crystallises in an orthorhombic lattice system (Cmcm space group), in Na[Sc(BH 4 ) 4 ] structure type [36], adopted also by M[RE(BH 4 ) 4 ], M ¼ Na, K, RE ¼ Y, Yb [19,49,37]. This structure consists of isolated [Ho(BH 4 ) 4 ] e anions and K þ cations (0D system) which form a distorted trigonal prism around the complex anion.…”