We report the synthes
is of a new sto
ich
iometr
ic Yb compound, Rb
3Yb
2(PO
4)
3, by h
igh-temperaturesolut
ion methods. Th
is
is the f
irst mater
ial of the A
3IB
2III(X
VO
4)
3 fam
ily conta
in
ing a lanthan
ide elementand the only one that shows opt
ical act
iv
ity. We resolved the structure of Rb
3Yb
2(PO
4)
3, wh
ich crystall
ize
in the cub
ic system, space group of symmetry
I2
13 (
a = 16.8700(10) &Ar
ing;, Z = 16), and stud
ied
its evolut
ionw
ith the temperature. The thermal expans
ion coeff
ic
ient of Rb
3Yb
2(PO
4)
3 is
![](/<font color=)
images/g
ifchars/alpha.g
if" BORDER=0> = 8.94 × 10
-6 K
-1. Th
iscompound melts
incongruently at 1450 K. The second-harmon
ic generat
ion eff
ic
iency of the Rb
3Yb
2(PO
4)
3,although l
im
ited as a result of the crystal not present
ing b
irefr
ingence, was at least s
im
ilar to that ofpotass
ium d
ihydrogen phosphate.