From the results of X-ray diffraction

it is certain that

R

VNb

2

O

9

(

R

=Y

Gd

La) can be obtained by solid state reaction with R

2

O

3

V

2

O

5

and Nb

2

O

5

.The luminescence properties of Eu

3+

and Dy

3+

in

R

VNb

2

O

9

(

R

=Y

Gd

La) have been systematically investigated. It is shown that host can sensitize Eu

3+

and Dy

3+

in these compounds. Eu

3+

occupies site with deviation from inverse center in

R

VNb

2

O

9

(

R

=Y

Gd

La)

because the intensity of

5

D

0

-

7

F

2

transition of Eu

3+

is stronger than that of

5

D

0

-

7

F

1

transition and the transition of

5

D

0

-

7

F

0

does not appear in these three matrixes(Fig. 1)

The red-to-orange intensity ratio (R/O) of Eu

3+

and the yellow-to-blue intensity ratio (Y/B) of Dy

3+

decrease with decreasing of the charge-to-radius ratio (

Z/r

) of R

3+

(Table 1).The influence of Bi

3+

and temperature on the emission intensity of Dy

3+

were also investigated

Bi

3+

acts as a "killer" for the emission of Dy

3+

.