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(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 tr

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: Chemical substances are provided which exhibit thermally induced spin transitions between two stable spin states at ambient temperature, said transitions being associated with a hysteresis phenomenon and resulting in an abrupt variation of the color of the molecules for realizing a medium for storing, processing and/or displaying information by way of thermal writing, optical reading and thermal erasing, a particular embodiment of such a medium comprising at least a layer of chemical substances including a lattice with a molecule comprising a metallic element Fe.sub.(II), or Fe.sub.(III) or Co.sub.(II) associated with at least one ligand chosen from the substituted triazoles which are defined by the formula: ##STR1## in which R is H or an alkyl C.sub.n H.sub.2n+1 or R is an amine group NL.sub.2 where L is H and an alkyl radical, said molecule also comprising one or several anions chosen, for example, from BF.sub.4.sup.-, ClO.sub.4.sup.-, Br.sup.-, Cl.sup.

Abstract: Chemical substances are provided which exhibit thermally induced spin transitions between two stable spin states at ambient temperature, said transitions being associated with a hysteresis phenomenon and resulting in an abrupt variation of the color of the molecules for realizing a medium for storing, processing and/or displaying information by way of thermal writing, optical reading and thermal erasing, a particular embodiment of such a medium comprising at least a layer of chemical substances including a lattice with a molecule comprising a metallic element Fe.sub.(II), or Fe.sub.(III) or Co.sub.(II) associated with at least one ligand chosen from the substituted triazoles which are defined by the formula: ##STR1## in which R is H or an alkyl C.sub.n H.sub.2n+1 or R is an amine group NL.sub.2 where L is H and an alkyl radical, said molecule also comprising one or several anions chosen, for example, from BF.sub.4.sup.-, ClO.sub.4.sup.-, Br.sup.-, Cl.sup.