Bis(3-methyl-1-propyl-1H-imidazol-3-ium) bis-(4,6-disulfanidyl-4,6-disulfanyl-idene-1,2,3,5,4,6-tetra-thia-diphosphinane-κ3 S 2,S 4,S 6)nickel.

The title salt, (PMIM)2[Ni(P2S8)2] (PMIM = 3-methyl-1-propyl-1H-imidazol-3-ium, C7H13N2 +), consists of a nickel-thio-phosphate anion charge-balanced by a pair of crystallographically independent PMIM cations. It crystallizes in the monoclinic space group P21/n. The structure exhibits the known [Ni(P2S8)2]2- anion with two unique imidazolium cations in the asymmetric unit. Whereas one PMIM cation is well ordered, the other is disordered over two orientations with refined occupancies of 0.798 (2) and 0.202 (2). The salt was prepared directly from the elements in the ionic liquid [PMIM]CF3SO3. Whereas one of the PMIM cations is well behaved (it does not exhibit disorder even in the propyl side chain), the other is found in two overlapping positions. The refined occupancies for the two orientations are roughly 80:20. Here, too, there appears to be little disorder in the propyl arm.

Investigation of hidden periodic structures on SEM images of opal-like materials using FFT and IFFT.

We have developed a method to use fast Fourier transformation (FFT) and inverse fast Fourier transformation (IFFT) to investigate hidden periodic structures on SEM images. We focused on samples of natural, play-of-color opals that diffract visible light and hence are periodically structured. Conventional sample preparation by hydrofluoric acid etch was not used; untreated, freshly broken surfaces were examined at low magnification relative to the expected period of the structural features, and, the SEM was adjusted to get a very high number of pixels in the images. These SEM images were treated by software to calculate autocorrelation, FFT, and IFFT. We present how we adjusted SEM acquisition parameters for best results. We first applied our procedure on an SEM image on which the structure was obvious. Then, we applied the same procedure on a sample that must contain a periodic structure because it diffracts visible light, but on which no structure was visible on the SEM image. In both cases, we obtained clearly periodic patterns that allowed measurements of structural parameters. We also investigated how the irregularly broken surface interfered with the periodic structure to produce additional periodicity. We tested the limits of our methodology with the help of simulated images.

Bis(1-ethyl-3-methyl-imidazolium) 3,6-diselanyl-idene-1,2,4,5-tetra-selena-3,6-diphospha-cyclo-hexane-3,6-di-selen-olate.

In the title compound, 2C6H11N2 (+)·P2Se8 (2-) or [EMIM]2P2Se8 (EMIM = 1-ethyl-3-methyl-imidazolium), the anions, located about inversion centers between EMIM cations, exhibit a cyclo-hexane-like chair conformation. The cations are found in columns along the a axis, with centroid-centroid distances of 3.8399 (3) and 4.7530 (2) Å. The observed P-Se distances and Se-P-Se angles agree with other salts of this anion.

Ionothermal synthesis of four new nickel thiophosphate anions: [Ni(P2S8)2]2­, [Ni(P3S9)(P2S8)]3­, [Ni(P3S9)2]4­, and [(NiP3S8)4(PS4)]7­.

Four new nickel thiophosphate anions have been isolated as 1-ethyl-3-methylimidazolium (EMIM) salts: [EMIM](2)[Ni(P(2)S(8))(2)] (1), [EMIM](3)[Ni(P(3)S(9))(P(2)S(8))] (2), [EMIM](4)[Ni(P(3)S(9))(2)] (3), and [EMIM](7)[(NiP(3)S(8))(4)(PS(4))] (4). Single crystals of each were prepared by ionothermal reaction of the elements in [EMIM][BF(4)]. 1 can also be obtained from [EMIM][CF(3)SO(3)]. In all four anions, Ni atoms are octahedrally coordinated and P atoms are tetrahedrally coordinated. In the anion found in 1, two tridentate 1,3-P(2)S(8)(2-) ligands are cis to each other. The anion in 2 contains two different tridentate thiophosphate ligands, 1,3-P(2)S(8)(2-) and P(3)S(9)(3-), whereas the anion in 3 consists of two P(3)S(9)(3-) ligands coordinated to the central Ni atom. The anion in 4 is complex, consisting of four NiP(3)S(8)(-) clusters surrounding a central PS(4) tetrahedron; within the NiP(3)S(8)(-) groups, one P atom is directly bound to Ni. The discovery of these four new compounds demonstrates the versatility of ionothermal methods for the synthesis of novel thiophosphates.

New three-dimensional thiostannates composed of linked Cu8S12 clusters and the first example of a mixed-metal Cu7SnS12 cluster.

Three new compounds (enH)(6+n)Cu(40)Sn(15)S(60) (1), (enH)(3)Cu(7)Sn(4)S(12) (2), and (trenH(3))Cu(7)Sn(4)S(12) (tren = tris(2-aminoethyl)amine) (3) containing Cu(8)S(12) and Cu(7)SnS(12) clusters have been prepared from direct solvothermal reaction of the elements in amine solvents. In 1, the cubic close-packed arrangement of Cu(8)S(12) clusters, interconnected by capping SnS(4) tetrahedra and CuS(3) triangles, form two interpenetrating channel networks that are presumably filled with disordered solvent molecules. Structures 2 and 3 contain well-ordered, protonated amine molecules and Cu(7)SnS(12) clusters. The clusters are connected by SnS(4) tetrahedra to form a three-dimensional structure with ReO(3) topology. (119)Sn Mössbauer measurement is consistent with Sn(IV) atoms linking, and Sn(II) atoms within, the mixed-metal Cu(7)SnS(12) clusters.

Solvothermal synthesis and structure of a new selenium-rich selenophosphate K(3)PSe(4).2Se(6).

The compound K(3)PSe(4).2Se(6) was synthesized at 110 degrees C via solventothermal techniques from binary starting materials and Se in acetonitrile. The compound crystallizes in the space group Fd macro 3 of the cubic system with eight formula units in a cell with a dimension of a = 16.415(2) A at T = 193 K. The structure contains an unusual intermixing of ionic and uncharged species. The selenophosphate tetrahedral trianions PSe(4)(3-) are surrounded by potassium cations; other potassium cations in the structure are coordinated to 12 selenium atoms from four Se(6) rings in a tetrahedral arrangement. There are no short contacts between adjacent selenium rings. Heating the same reaction mixture to 160 degrees C results in the formation of only needles of trigonal selenium.

Synthesis and Structure of the Layered Thorium Telluride CsTh(2)Te(6).

The compound CsTh(2)Te(6) has been synthesized at 800 degrees C by the reaction of Th with a Cs(2)Te(3)/Te melt as a reactive flux. The compound crystallizes in the space group -Cmcm of the orthorhombic system with two formula units in a cell of dimensions a = 4.367(2) Å, b = 25.119(10) Å, c = 6.140(3) Å, and V = 673.5(5) Å(3) at T = 113 K. The structure of CsTh(2)Te(6) has been determined from single-crystal X-ray data. The structure comprises infinite, two-dimensional double layers of ThTe(8)-bicapped trigonal prisms. The structural motif of the trigonal prisms resembles that found in UTe(2). Cs(+) cations, disordered equally over two crystallographically equivalent sites, separate the layers and are coordinated by eight Te atoms at the corners of a rectangular parallelepiped. Short Te-Te distances of 3.052(3) and 3.088(3) Å form linear, infinite, one-dimensional chains within the layers. Simple formalisms describe neither the Te-Te bonding in the chain nor the oxidation state of Th. The compound shows weak semiconducting behavior along the Th/Te layers perpendicular to the Te-Te chain.