Material Name:	Heulandite
	Chemical Formula:	|Ca4 (H2O)24 | [Al8Si28O72]-HEU
	Unit Cell:	monoclinic	C 1 m 1 (# 8)
		a' = 17.7180 Å	b' = 17.8970 Å	c' = 7.4280 Å
		α' = 90.000°	β' = 116.420°	γ' = 90.000°
	Framework Density:	17.1 T/1000 Å3

Channels:

{[001] 10 3.1 x 5.5* + 8 4.1 x 4.1*} <-> [100] 8 2.8x 3.4* (variable due to considerable flexibility of framework) Dimensionality   Sorption (molecular cross section > 3.4Å): 1-dimensional   Topological (pore opening > 6-ring): 2-dimensional

	References:
		Alberti, A.
			"On the Crystal Structure of the Zeolite Heulandite"
			Tschermaks Min. Petr. Mitt., 18, 129-146 (1972)
		Merkle, A.B. and Slaughter, M.
			"The crystal structure of heulandite (Ca,Na2)[Al2Si7O18]·6H2O"
			Am. Mineral., 52, 273-276 (1967)
			Material name:   Heulandite
			Chemical formula:   [Al8Si28O72]-HEU

	Name and Code derivation:
		Heulandite   HEU