Abstract: A chemical composition is provided for the manufacture of devices for storing and/or displaying information, comprising a network having a molecule which is formed from a metallic element Fe(II) which is bonded to a 1-2-4 triazole ligand (H-Trz), which molecule further comprises one or more than one anions A selected from BF4−, ClO4−, CO32−, Br−, Cl−, in accordance with the formulation: FeII(H-Trz)3A2, characterized in that this composition is used in the pure state in either one of the two crystalline phases (&agr;,&bgr;) at least one of which, referred to as the second phase (&bgr;), can be thermally induced on the basis of the other phase, referred to as the first phase (&agr;), at a temperature which is equal to or higher than a first reference temperature (To), which phases each show thermally inducible spin transitions between a low-spin state at a low first temperature (T&agr;1, T&bgr;1) and a high-spin state at a high second temperature (T&agr;2, T&bgr;2), the spin tran

Abstract: A chemical composition is provided for the manufacture of devices for storing and/or displaying information, comprising a network having a molecule which is formed from a metallic element Fe.sub.(II) which is bonded to a 1-2-4 triazole ligand (H-Trz), which molecule further comprises one or more than one anions A selected from BF.sub.4.sup.-, ClO.sub.4.sup.-, CO.sub.3.sup.2-, Br.sup.-, Cl.sup.-, in accordance with the formulation:Fe.sub.II (H-Trz).sub.3 A.sub.2,characterized in that this composition is used in the pure state in either one of the two crystalline phases (.alpha., .beta.) at least one of which, referred to as the second phase (.beta.), can be thermally induced on the basis of the other phase, referred to as the first phase (.alpha.), at a temperature which is equal to or higher than a first reference temperature (To), which phases each show thermally inducible spin transitions between a low-spin state at a low first temperature (T.sub..alpha.1, T.sub..beta.

Abstract: The invention relates to a spin-transition parent compound in powdered form, comprising a network having molecules which are each formed from a complex in which a metallic ion M having an electronic configuration in d5 or in d6 or in d7, is bonded to at least one aminotriazole ligand of the formula ?L.sub.2 N-trz!, wherein L is an alkyl radical (C.sub.n H.sub.2n+1) and n is an integer which is equal to or greater than zero, each molecule also including a sulforganic anion comprising a sulfito radical (SO.sub.3.sup.-), and the network also including at least one water molecule (H.sub.2 O) per molecule of the metallic complex M, said water molecule(s) in the network only being bonded to the aminotriazole ligand by a hydrogen bond.In this compound, the anion may be, for example, a sulfito-aryl having a benzene radical or a sulfito-aryl derived from a benzene radical, or a sulfito-aryl having a saturated or unsaturated organic chain, an alkyl sulfito-halide or an aryl sulfito-halide.