In IF7 out of 7 Flourine atoms 5 of them are placed on a plane in Pentagon shape .In remaining 2 flourines one is placed above the plane and other below the plane each at 90 degrees
As you move down, the numbers represent multiples of 12,subtracting 1 for the first step,adding 2 for the second, subtracting 3 for the third, adding 4 for the next ect.ect