Considering solid state reaction, simply you can obtain the general formula

(1-x)SrO + (1+x) TiO2= Sr(1-x)Ti(1+x)O(3+x)

and the rest depends upon the amount of each solid solution and its dopant concentration you want to prepare. In addition, the Mol.Wt. of starting Sr- and Ti- materials should be known

In general, you can mix in grams the starting materials as [(1-x) * Mol.Wt. of Sr- compound ]/n + [(1+x) * Mol.Wt. of Ti- compound]/n

n is the mass factor. its numerical value is based on weight of solid solution you want to obtain.

I hope this will help you

I think, it is not necessary to dope titanium (Ti) in strontium titanate (SrTiO3). Because, titanium is one of the element in SrTiO3 compound (one mole Ti is presented in SrTiO3).

@Krishnan Rajagopalan Thanks.Later I also thought the same.But can you please tell what kind of nitrate compound is needed to dope nitrogen in TiO2/TiB2?

There are different ways, to dope nitrogen e.g. ammonia, triethylamine and urea. Hope these research papers will help you.

1) http://www.sciencedirect.com/science/article/pii/S0013468611003185

2) http://www.sciencedirect.com/science/article/pii/S1876610213010527

3) http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.96.026103

@Kamran Rasool thanks for your kind information.I will surely look at those papers you have refereed.