Moong and Mung bean

Mung bean is a synonym for moong. In some cases you can use "Mung bean" instead a noun "Moong".

Mung bean noun - Erect bushy annual widely cultivated in warm regions of India and Indonesia and United States for forage and especially its edible seeds; chief source of bean sprouts used in Chinese cookery; sometimes placed in genus Phaseolus.

Moong is a synonym for mung bean. You can use "Moong" instead a noun phrase "Mung bean".