Robert C. Haushalter

Structure of a Three-Dimensional, Microporous Molybdenum Phosphate with Large Cavities

The synthesis, single-crystal x-ray structural characterization, and sorption properties of a microporous molybdenum phosphate, (Me4N)1.3(H3O)0.7[Mo4O8(PO4)2] � 2H2O (Me, methyl), are presented. The three-dimensional framework is built up from Mo4O84+ cubes and PO43- tetrahedra that are connected in such a way that large, cation-filled voids are generated; these voids constitute 25% of the volume of the solid. Absorption isotherms for water show the completely reversible uptake of 4 to 5 percent by weight water into the micropores of this compound, which corresponds to 10 to 12 percent by volume.

Layer and tunnel structures in new molybdenophosphates: Cs2Mo4P6O26 and M4Mo8P12O52 (M = Cs, Rb, K, Tl)

Crystals of Cs2Mo4P6O26 and Cs4Mo8P12O52 were both discovered in the same reaction product obtained from heating a stoichiometric mixture of Cs2MoO4, MoO3, MoO2, and P2O5 in an evacuated quartz tube at 800°C. For Cs2Mo4P6O26, monoclinic, P2c, a = 7.479(3), b = 8.461(5), c = 9.018(2) A, β = 101.99(3)°, V = 558.2(7) A3, Z = 1, and R = 0.045, Rw = 0.053 for 936 independent reflections. For Cs4Mo8P12O52, monoclinic, P21, a = 6.398(1), b = 19.497(6), c = 9.835(2) A, β = 107.06(3)°, V = 1173(1) A3, Z = 1, and R = 0.046, Rw = 0.058 for 1398 independent reflections. Cs2Mo4P6O26 consists of layers of molybdenum phosphorus oxide with the cesium atoms between the layers. Each layer is built up from corner-sharing MoO6 octahedra, PO4 tetrahedra, and pyrophosphate groups, P2O7. Cs4Mo8P12O52 is composed of the same building units arranged in a different way to give rise to tunnels where the cesium cations reside. The rubidium, potassium, and thallium analogs of Cs4Mo8P12O52 were also prepared. The Cs2Mo4P6O26 structure is closely related to that of K4Mo8P12O52 (A. Leclaire, J. C. Monier, and B. Raveau, J. Solid State Chem. 48, 147 (1983)).

Crystal structure and magnetic properties of a new molybdenophosphate: AgMo5P8O33

Abstract The crystal structure of AgMo5P8O33 has been determined from single-crystal X-ray diffraction data. AgMo5P8O33 crystallizes in the monoclinic space group I2 a (#15) with a = 23.050(8), b = 4.831(4), c = 22.935(9), A, β = 90.42(5)°, V = 2554(4), A3, Z = 4, R = 0.086 (Rw = 0.089) for 879 reflections with F2o > 3.0σ(F2o). The structure consists of large tunnels where the silver atoms are located. The framework is built up from MoO6 octahedra and P2O7 groups. The connectivity formula for AgMo5P8O33 is Ag(MoO 1 1 O 4 2 )(MoO 1 1 O 5 2 ) 4 (P 2 O 1 1 O 6 2 ) 4 . Powder magnetic susceptibility data confirm the presence of Mo5+ (d1) ions with spin 1 2 , and a featureless antiferromagnetic ordering appears to occur below 2.5 K. Magnetization isotherms at 1.3 and 4.2 K in magnetic fields up to 65 kG are reported. The lithium, sodium, calcium, strontium, barium, and lead analogs of AgMo5P8O33 were also prepared.

Group 10 telluride and polytelluride complexes: Synthesis and structures of Pd(Te4)22− and (Ph3P)2Pt(μ-Te)2Pt(PPh3)2

Abstract PdCl 2 reacts with K 2 Te 4 in DMF to produce Pd(Te 4 ) 2 2− , which was isolated as a bis-PPh 4 + salt. The X-ray structure of this compound revealed a square-planar palladium atom with two chelated Te 4 2− ligands. Pt(PPh 3 ) 4 reacts with (Bu 4 N) 4 Hg 4 Te 12 in DMF to produce (Ph 3 P) 2 Pt(μ-Te) 2 Pt(PPh 3 ) 2 which was also characterized by single-crystal X-ray diffraction.

Puckered hexagonal nets in 2∞[Sn33As−33] and 2∞[Sn33Sb−33]

Abstract The new compounds KSnAs and KSnSb have been prepared and their crystal structures have been determined from X-ray powder diffraction patterns. Both compounds crystallize in hexagonal systems (space group P6 3 mc; a = 4.1032(5) A , c = 12.845(2)A for KSnAs and a = 4.359(1) A , c = 13.150(3) A for KSnSb). The structures contain puckered sheets, with the Sn and As (or Sb) segregated on opposite sides of each sheet and with the potassium cations between the sheets.

Unusual magnetic behavior of the amorphous metallic materials M2SnTe4 where M=Co and Ni

Abstract The magnetic properties of three ternary metal chalcogen materials are reported. Ni2SnTe4 exhibits a temperature independent paramagnetism over the entire temperature range 6–300 K. It also exhibits a weak magnetic remanence consistent with an itinerant ferromagnet. Co2SnTe4 exhibits a spin glass transition with a weak ferromagnetic component and a freezing temperature Tf = 5 K.

A mixed valence heteropolyvanadate, K7Na[AsV4VV7VIV5O43H3]·7H2O

Abstract The reaction of NaVO3 with As2O3, Na2C6O6 and KSCN in water at pH 4.4 yields shiny black crystals of K7Na[AsV4VV7VIV5O43H3]·7H2O. The structure consists of an ϵ-Keggin core {AsV12O40} with three [VO] vertices removed and capped by three [VO] and three [AsOH] units. Crystal data: monoclinic C2/c, a = 40.048(9), b = 13.326(1), c = 18.074(3) A, β = 112.28(1)°, V = 9005.9(14) A3, Dcalc = 2.986 g cm−3, Z = 8, R = 0.063 for 5999 reflections.

Transmission electron microscopy study of the reaction of Sn4−9 zintl ions with single crystal Au films

Abstract The solid reaction products resulting from the interaction of solutions of Sn 4 − 9 Zintl ions with [001] oriented 20 nm thick single crystal Au foils have been analyzed by various transmission electron microscopy techniques. It is found that hexagonal AuSn and free β-tin are the principal reaction products, with evidence of trace amounts of other crystalline phases tentatively identified as AuSn2, AuSn4 and K2Sn3O7, in heavily exposed samples. A significant amount of unreacted Au remains even after long exposure to saturated solutions, suggesting that the initial reaction products tend to inhibit further reaction with the Au foil. With exposure to increasing Sn 4 − 9 concentration the AuSn, however, does not appear to cover the Au as a uniform passivating layer but instead, in some areas, grows as fibers that can penetrate the Au foil. There is a preferred growth orientation such that the AuSn [0001] axis always lies within the plane defined by the Au [001] and [110] axes, and such that the AuSn [1210] direction remains parallel to the Au [110] direction, within the plane of the foil. This gives rise to selected area diffraction patterns which are a mixture of sharp spots and rings, characteristic of strong textured-fiber epitaxial growth.

Parallel, segregated Cs+- and K+-filled one-dimensional tunnels in Cs2K2Mo8P12O52

Abstract The reaction of Cs2MoO4, K2MoO4, MoO3, Mo, and P2O5 in a mole ratio of 1:1:4.33:1.33:6 in an evacuated silica tube for 48 hr at 900°C yields dichroic crystals (green when viewed parallel to the normal of the {010} sets and yellow when viewed parallel to the normal of the {001} sets) of Cs2K2Mo8P12O52. The crystals are monoclinic, space group P2 1 c (#14) with a = 6.388(2), b = 18.901(2), c = 18.805(2)A, β = 92.07(2)°, and V = 2269.11(9)A3. The framework consists of (MoO6) octahedra, (PO4) phosphate, and (P2O7) pyrophosphate groups and contains two different types of parallel tunnel: a large tunnel in which an ordered array of Cs+ and voids are found and a smaller one filled with K+.

The tellurium analogue of the hydroxide ion: Syntheses and structure of (PPh4)TeH

Abstract Treatment of the ethylenediamine (en) extracts from solids of nominal composition K2SiTe3 and K2GeTe3 with (PPh4)Br, gives the tetraphenylphosphonium salt of the hydrogen tellurium (1 −) anion, (PPh4)TeH (1). Telluride (1) was identified by elemental analysis, IR spectroscopy and a single crystal X-ray structure determination. Crystals of 1 were isomorphous with tetragonal (PPh4)Br, space group I 4 , with cell constants at − 160°C of a = 11.945(7), c = 6.867(3) A, Z = 2 and V = 979.8 A3.