Centring objects in the border of a circle

Milomolly, you have several good answers. Please mark one as correct.

This is another way, as there can be several solutions with the same result.

-I usually draw a blue circle that is the exact width of the inner and outer circle space and align horizontally and vertically with the icon. Group the icon and blue circle.

-Next, I select both black circles and the blue circle icon group, and align everything to horizontal center. Then I take my blue circle and icon, and with snap to point turned on under the view menu, I will snap the left point in the blue circle shape to the outermost black circle. Then I will duplicate the blue circle and icon to the opposite side (snapping tthe right point of the blue circle to the far right of the black outer circle point). Finally, I select just the blue circles and delete them.

Molly,

You may, even without knowing the sizes of the circles, Smart Guides being your friends:

1) With the Line Tool ClickDrag between the leftmost Anchor Points of the two circles, repeat for the right side;

2) Select both lines and Object>Path>Add Anchor Points;

3) ClickDrag each geo icon by its centre to snap to the midpoint from 2);

4) Delete the two lines.

Turn on your rulers and drag guide lines to the center of your circle, selecting both small objects will show you the center point of the objects, snap this point to your guides.

If this is a "one-ff" thing, I'd create a shape the width of the target space and align to the shape, then delete the shape.