Molecular clouds

What are molecular clouds and how do they differ from the rest of the interstellar medium? What is a dark cloud? Molecular Cloud is a large dense area of gas and dust in the space. It is made mostly of molecular Hydrogen and Helium. Interstellar medium Composed of approximately 99 percentage of gas (90% of it is molecular or atomic hydrogen, 9% is helium) and 1 percentage of dust. Molecular cloud is composed entirely of molecules. It is primarily made of molecular hydrogen, but many other molecules are composed of hydrogen, carbon, nitrogen and oxygen. Compared to interstellar medium molecular Cloud has large density and they are very clod. Molecular clouds are also the largest inhabitants of our galaxy. Dark cloud is a cloud in our galaxy, which is made of dust. Dark cloud has typical densities of a few tens or hundreds of millions of particles per cubic meter. Giant molecular clouds are more than a million times as massive as the Sun. They contain dense gas and dust enough to form thousand of sun like stars. The average temperature of dark cloud range from -440 to -370 degree Fahrenheit.