Na

5

Eu(MoO

4

)

4

is a stoichiometric host luminescent material. If H

2

WO

4

and Na

2

WO

4

are added as reactants in synthetic process of Na

5

Eu(MoO

4

)

4

the Na

5

Eu(Mo

1-x

W

x

O

4

)

4

system will be synthesised. When 0

<

x

<

0.21

the fluorescence spectrum of the system

is almost the same as Na

5

Eu(MoO

4

)

4

and the intensity of main emission peak is higher than that of latter. The maximal increase is about 30% when x is 0.033. The X-ray powder diffraction analysis shows that when the value of x increases

the ratio of crystal cell parameter c/a decrease. It means that W ions enter into the lattice of Na

5

Eu(MoO

4

)

4

. The reason of enhancement by W might be related to the change of crystal field environment of Eu

3+

. If SiO

2

is added as a reactant in synthesis process of Na

5

Eu(MoO

4

)

4

when the molar ratio of Si to(Si+Mo)

y

in 0

<

y

<

0.08

the intensity of main peak will increase and the maximal increase is about 50% when

y

=0.028. According to X-ray diffraction analysis

the reason of enhancement might be related to alpha cristobe-lite which is formed by added SiO

2

and forms the encapsulation of Na

5

Eu(MoO

4

)

4

.