How to prevent an object from instantiating inside another object?

So I have a sphere game object that I want to instantiate. I've been able to get it so that when you click on a sphere or its clone that another instantiation doesn't occur. However, when I click right next to the sphere, another sphere is created that meshes with the other. Here's my code and see if you can try to help me:

 using UnityEngine;
 using System.Collections;
 
 public class Instantiate : MonoBehaviour {
     Ray ray;
     RaycastHit hit;
     public GameObject Sphere;
     public int count;
     public Transform teleport1;
     public Transform teleport2;
     public GameObject Cube;
 
     void OnTriggerEnter(Collider other) //This is where I've tried to stop the meshing, but to no avail.
     {
         if(other.gameObject.CompareTag ("Sphere"))
     {
             other.gameObject.Destroy;
         }
     }
     void Update ()
     {
         if(Input.GetButtonDown("Fire1"))
         {
             Cube.transform.position = teleport1.position;
         }
         if(Input.GetButtonDown("Fire2"))
         {
             Cube.transform.position = teleport2.position;
         }
 
 
             ray = Camera.main.ScreenPointToRay (Input.mousePosition);
         if (Physics.Raycast (ray, out hit))
         {
             if (Input.GetMouseButtonDown (0))
             {
                 if(hit.transform.name != "Sphere" && hit.transform.name != "Sphere(Clone)")
                 {
                 Instantiate (Sphere, hit.point + new Vector3(0, 0.5f, 0), Quaternion.identity);
                 count = count + 1;
 
                 }
 
 
             }
         }
     }
 }