Colour of the compounds mainly depends on the purity of the compound after column purification or any other method used for purification. The same compound if you do crystallization or precipitation or lyophilization again there is a slight change in the colour. Better to mention always colour of the compound on the basis of assay purity. Many nitro compounds shows yellow in colour.

NTO is a white to pale yellow crystalline powder.

NTO is white in color, presence of nitrone gives yellowish shade

Thank you dear for your answers. That was helpful.

best regards

AHMED FOUZI TARCHOUN

It is very pale yellow

Dear professor Faiq H S Hussain thank you for your answer.

Yes, yellowish color possible.

Dear professor Md.Kudrat-E- Zahan

thank you for your answer.