we have a building and we have one side only available to install the rods, as per design we have to install 100 rods in area 76m x 3m (ROCK) to reach 2 ohm or less , then we have not any choice , the spacing will be 1.5m (4.9 feet) , , or we have to think about another solution by using PLATE/LATTICE ??
Wow!
Looks like a job for an EE who can actually look at the site. Somewhere along the way there has to be conductivity testing done on the rock or rocky soil.
If the resistance of the rock is high enough, then there may be no type of electrode that will fit into that space and give you the resistance you need.
Wet limestone is pretty good. Wet or dry quartz is pretty hopeless.
Is the rock solid enough that you will have to be drilling the holes for the ground rods? That would be a bad sign.
A poured UFER ground (not necessarily meeting the NEC definition of a CEE, but still quite usable for meeting your specification) may be the best way to go.
If you are limited in the depth to which you can go, a plate or lattice will not be a lot better (factor of two maybe?) than a network of rods that covers the same area and goes to the same depth.