The te
rna
ry gallides Ce(Rh
1-xI
rx)Ga with
x = 0, 0.54, and 1 we
re synthesized f
rom the elements bya
rc-melting. The st
ructu
res of these inte
rmediate valence compounds we
re investigated on the basis ofpowde
r and single-c
rystal X-
ray diff
ractomete
r data: TiNiSi type,
Pnma,
a = 688.2(2),
b = 439.6(1),and
c = 788.9(1) pm, w
R2 = 0.0493, 563
F2 values, and 20 va
riable pa
ramete
rs fo
r CeRhGa;
a =685.5(1),
b = 436.0(1), and
c = 782.7(1) pm, w
R2 = 0.0685, 563
F2 values, and 21 va
riable pa
ramete
rsfo
r Ce(Rh
0.46I
r0.54)Ga; and
a = 690.1(1),
b = 436.6(1) and
c = 785.2(2) pm, w
R2 = 0.0810, 562
F2values, and 20 va
riable pa
ramete
rs fo
r CeI
rGa. The
rhodium (o
r i
ridium) and gallium atoms build upth
ree-dimensional [RhGa] and [I
rGa] netwo
rks with Rh-Ga (o
r I
r-Ga) distances
ranging f
rom 265 to267 pm (o
r f
rom 265 to 269 pm). The ce
rium atoms fill disto
rted hexagonal channels within these netwo
rkswith one sho
rt Ce-Rh (o
r Ce-I
r) contact (281 pm in CeRhGa, 283 pm in Ce(Rh
0.46I
r0.54)Ga, and 287pm in CeI
rGa). Hyd
rogenation leads to the fo
rmation of the hyd
rides Ce(Rh
1-xI
rx)GaH
1.8 in going witha switch in st
ructu
re type: Z
rBeSi type,
P6
3/
mmc,
a = 437.3(1) and
c = 839.2(1) pm fo
r CeRhGaH
1.8,
a = 440.1(1) and
c = 829.1(1) pm fo
r Ce(Rh
0.46I
r0.54)GaH
1.8, and
a = 441.8(1) and
c = 823.3(1) pm fo
rCeI
rGaH
1.8. Susceptibility and specific heat measu
rements on the hyd
rides
reveal stable t
rivalent ce
riumand antife
rromagnetic o
rde
ring at low tempe
ratu
res; the N&
eacute;el tempe
ratu
re dec
reases with the
rhodiumcontent. Fitting of the susceptibility data of the hyd
rides conside
ring the c
rystal field splitting and molecula
rfield effects clea
rly
revealed the doublet
r.gif">
9 =
rba
r.gif"> ±
3/
2 as the g
round state. Elect
rical
resistivity data andthe
rmoelect
ric powe
r measu
rements show the cha
racte
ristics of Kondo systems.