Ce₂Ga₁₀Ni – a member of R_mX_4m+2nX_nseries of nonhomogeneous linear structures

Abstract

Indexing of these reflexions gave space group P622 with a unit cell related to the r>Jn 5 Si 3 cell by c5 ~ 3c, a5 ~ a-b, bb ~ a+Zb. Intensities were collected on Lu 5 Ir 3 single crystal. Fourier maps have shown disorder along the c a.xis. Using the fact that hko data did not contain any superstructure reflexions, atoms should be split with different z values as it has been made for Eu 5 As

Crystal growth and properties of Ln2Ag1−xGa10−y (Ln=La, Ce), a disordered variant of the Ce2NiGa10-structure type

“…Select interatomic distances of La 2 Ag 0.7(1) Ga 9.4(1) and Ce 2 Ag 0.7(1) Ga 9.1(1) are provided in Table 3. The Ga-Ga and M-Ga (M¼Ag+ Ga) bond distances are $2.5 and $2.6Å which are consistent with other AgGacontaining intermetallic compounds and with similar distorted gallium networks [20][21][22][23][24][25][26][27][28][29][30][31][32]38,41,46].…”

“…This includes Ga-Ga contacts as well as Ga-T (T¼ transition metal) contacts in these phases. In previously reported YbGa 5 , a coordination of four can be obtained for all the Ga atoms by applying limits on interatomic distances found in previously published Ln:Ga (Ln ¼lanthanide) binary and Ln:Ag:Ga (Ln ¼lanthanide) ternary phases [20][21][22][23][24][25][26][27][28][29][30][31][32]. This approach results in the three most-likely components, shown in brackets 1-3 of Fig.…”

“…In the distorted bicapped Ga cubes of YbGa 5 , the authors suggested that the intrinsic disorder and split atom positions stem from the tendency of Ga to achieve the optimum coordination of four [41]. Previously published Ln:Ga (Ln ¼lanthanide) binary and Ln:Ag:Ga (Ln¼lanthanide) ternary phases depict Ga in a four coordinate environment (with interatomic contacts between 2.5 and 2.6Å) [20][21][22][23][24][25][26][27][28][29][30][31][32]. This includes Ga-Ga contacts as well as Ga-T (T¼ transition metal) contacts in these phases.…”

“…139) with crystallographic parameters provided in Table 1. The crystal structures of Ln 2 Ag 1 À x Ga 10 À y (Ln¼La, Ce) can be viewed as disordered variants of Ce 2 NiGa 10 [32,39]. As shown in Fig.…”

“…Although the structure of several Ln:Ag:Ga (Ln ¼lanthanide) intermetallic compounds such as Ln(Ag,Ga) 4 (Ln¼ La-Nd, Sm, Yb) [20,21], Ln 3 (Ag,Ga) 11 (Ln ¼Y, Gd-Yb) [22,23], LnAgGa 2 (Ln¼Gd, Yb, Y) [23][24][25], LnAgGa (Ln ¼Tb-Ho) [26], Ln(Ag,Ga) 2 (Ln ¼La-Nd, Sm-Lu, Y) [23,27,28], Ln 5 (Ag,Ga) 19 À x (Ln¼Gd, Tb; x $ 2.2) [29], CeAg 4.12 Ga 6.88 [30], CeAg 1.25 Ga 4.25 [30], Gd 14 (Ag,Ga) 51 [25], Gd(Ag,Ga) [25], and Ln(Ag,Ga) 3 (Ln ¼Sm, Gd, Tb-Tm, Lu) [31] have been reported, the structure determination of most are from polycrystalline samples and the physical properties of most of these compounds have not been investigated. Here we report the flux growth and characterization of Ln 2 Ag 1 À x Ga 10 À y (Ln ¼La, Ce), a disordered variant of the Ce 2 NiGa 10 structure-type [32]. We will compare Ce 2 Ag 1 À x Ga 10 À y (x $0.3; y$ 0.9) to Ce 2 NiGa 10 to examine the structural changes with transition metal substitution and to the structurally related Ce(Ag,Ga) 4 [14,20,33,34] (BaAl 4 -structure type) to examine the effects of crystal structure on the physical properties.…”