Unity2D - How to create a dictionary or hashtable in C#?

Question

I'm trying to keep track of some variables and keep my code efficient. I know the Unity API contains hashtables but it doesn't explain how to use them and/or it just straight up doesn't work. I've also tried the Microsoft C# version of dictionaries but that doesn't seem to work either. Here is the code I want to work:

public Hashtable OrbitSpeeds = new Hashtable();
//This doesn't work//
OrbitSpeeds.Add("Moon", 1.0f);
OrbitSpeeds.Add("Sattelite", -2.5f);
OrbitSpeeds.Add("Cloud", -3.0f);
float newSpeed = OrbitSpeeds["Cloud"];
OrbitSpeeds["Moon"] = 2.0f;

Dictionary <string, float> OrbitSpeeds = new Dictionary<string, float>();
//This also doesn't work//
OrbitSpeeds.Add("Moon", 1.0f);
OrbitSpeeds.Add("Sattelite", -2.5f);
OrbitSpeeds.Add("Cloud", -3.0f);
float newSpeed = OrbitSpeeds["Cloud"];
OrbitSpeeds["Moon"] = 2.0f;

Answer 1

It turns out the way to initialize and add things is to do it as so:

public class TAGS : MonoBehaviour
{
    public static Dictionary<string, float> OrbitSpeeds= new Dictionary<string, float>
    {
        {"Moon", 1.0f},
        {"Sattelite", -2.5f},
        {"Cloud", -3.0f}
    };
}

And this works exactly as intended