The Pentropic organisation was a military organisation used by the Australian Army between 1960 and 1965. It was based on the United States Army's pentomic organisation and involved reorganising most of the Army's combat units into units based on five elements, rather than the previous three or four sub-elements. The organisation proved unsuccessful, and the Army reverted to its previous unit structures in early 1965.
Then Brigadier Reg Pollard in Korea, 1953. As Chief of the General Staff, Pollard oversaw the restructure of the Australian Army along pentropic lines.
Then Colonel John Wilton in Morotai, September 1945. As Chief of the General Staff, Wilton later commissioned a review that ultimately recommended a return to the triangular formation.
Pentomic was a structure for infantry and airborne divisions adopted by the US Army between 1957 and 1963, in response to the potential use of tactical nuclear weapons, on future battlefields. It was intended that the five subordinate units, which were often referred to as battle groups, would be able to deploy and engage in operations more rapidly than conventional brigades, whilst also having greater offensive capabilities than conventional battalions.
1960 Pentomic Infantry Division. The five "Battle Groups" on the left of the diagram dominate the Divisional structure.
