Hydrogen Impurity Effects. A5Tt3 Intermetallic Compounds between A=Ca, Sr, Ba, Eu and Tt=Si, Ge, Sn with Cr5B3-like Structures that are Stable Both as Binary and as Ternary Hydride and Fluoride Phases

High-pressure Synthesis of Strontium Hexasilicide

“…However, SrSi and SrSi 2 exhibit metallic conductivity. With respect to the electron count, the phases fulfil the 8 − N rule so that these compounds are silicides composed of Sr 2+ and isolated Si 4− in Sr 2 Si [22], isolated Si 4− and (1b)Si 3− (Si 6− 2 dumbbells) in Sr 5 Si 3 [23,24], (2b)Si 2− chains in SrSi [25,26] or a mixture of (1b)Si 3− , (2b)Si 2− and (3b)Si − in a second modification of SrSi comprising condensed-chain fragments [27], and finally (3b)Si − in the networks of dimorphic SrSi 2−x [28 -32]. The 3D network in the new compound SrSi 6 is formed by four-bonded silicon atoms (4b)Si 0 .…”

Two Germanide Hydride Phases Grown in Calcium‐Rich Flux: Use of Interstitial Elements for Discovery of New Phases

“…In the Ca/Ge slab, Ge(1) atoms are coordinated by 10 calcium atoms at distances ranging from 3.04 to 3.68 Å (see Table 1); the Ge-Ca interatomic distances in Ca 2 Ge and Ca 5 Ge 3 are also in this range. [2,11] The Ge(2) atoms in the hydride slab are coordinated more strongly to 6 calcium atoms in a trigonal-prismatic distribution with bond lengths of 2.93-2.96 Å. These trigonal prisms share edges with hydride-centered octahedra to form the hydride germanide slabs (see Figure 2).…”

“…Synthesis of a fluoride analogue (LiCa 11 Ge 3 OF x ) would also aid in the structural analysis; F -can in many cases occupy hydride sites, and this heavier atom is easier to locate in crystal structure refinement. [2,7] However, reactions of Ge, CaO, and CaF 2 have not yielded isostructural products.…”

“…This property has been used to remove hydride impurities from metals. [2] Since synthesis in Ca/Li flux favors the formation of calcium-rich phases that incorporate a range of interstitial elements, it is extremely difficult to control the synthesis to isolate only one of the observed calcium-and germanium-containing products (Ca 2 Ge, LiCa 7 Ge 3 H 3 , and LiCa 11 Ge 3 OH 4 ). Pure Ca 2 Ge can be obtained in a wellcrystallized form from reaction of Ge in Ca/Li flux made with distilled Ca; the unit-cell parameters of these crystals match those reported in the literature for the orthorhombic structure.…”

“…[1][2][3][4][5][6][7] Incorporation of hydride anions is of particular interest; the difficulty in detecting this element in X-ray crystallography studies has led to reports of phases with ostensibly electronrich structures and stoichiometries. Compounds such as Ba 21 M 2 O 5 (M = Ge, Si) and Ba 5 Ga 6 were found to have incorporated hydrides, leading to their reclassification as charge-balanced Zintl phases (Ba 21 M 2 O 5 H 24 and Ba 5 Ga 6 H 2 , respectively).…”