The latter 'material particle' is nothing but the primary matter that forms the basic object of physical inquiry. Physics can't go further back. Only philosophical thinking can produce reliable answers concerning reality before the existing matter. So here follow some philosophical remarks on the case. There is no space on itself.
Space is a configuration of four 'immaterial particles'.
This explains why space isn't touchable. When four other 'immaterial particles' join such a system in a special way this space creates movements in four different directions. Since these movements are caused by 'immaterial particles' they are pure energetic movements that point to fully different directions. The focus of these energetic movements, situated in the center of the space within the four particles, is in combination with its surrounding eight particles the very first 'material particle'. It is the so-called point in space that is known in mathematics.