... , 5-valent (dark blue) - 4 pieces, atom of nitrogen 3-valent (dark blue) - 4 pieces, atom of oxygen 2-valent ... ) - 8 pieces, atom of phosphorus 5-valent (violet) - 4 pieces, flexible connecting elements - 80 pieces, model Benzol rings - 3 pieces, a ... suitcase for storage and transporting the equipment, universal elements - 4 ...