Ce4Ag3Ge4O(0.5)--chains of oxygen-centered [OCe2Ce(2/2)] tetrahedra embedded in a [CeAg3Ge4] intermetallic matrix.
The oxidation of an intermetallic phase under high-pressure/high-temperature conditions led to the synthesis of Ce4Ag3Ge4O(0.5) exhibiting [OCe2Ce(2/2] tetrahedral chains, in which the oxygen atoms statistically occupy the tetrahedral centres. Starting from a 1:1:1 CeAgGe precursor (NdPtSb type), a multianvil high-pressure/high-temperature experiment at 11.5 GPa and 1250-1300 °C revealed Ce4Ag3Ge4O(0.5), crystallizing in the space group Pnma with the following lattice parameters: a = 2087.3(4), b = 439.9(1), and c = 1113.8(2) pm. Magnetic measurements showed Curie-Weiss behavior above 100 K with an experimental magnetic moment of 2.42 µB per Ce atom, close to the value for the free Ce(3+) ion, clearly indicating trivalent cerium in Ce4Ag3Ge4O(0.5). Full potential GGA+U band structure calculations resulted in metallic properties and a magnetic ground state with one unpaired 4f-electron per cerium in agreement with the experiments.
The Oxidation of Heterogeneous Tl/Ni/P-Alloys — Preparation and Crystal Structures of the Thallium Nickel Phosphates TlNi4(PO4)3, Tl4Ni7(PO4)6, and Tl2Ni4(P2O7)(PO4)2
Single crystals of the first anhydrous thallium nickel phosphates were prepared by reaction of heterogeneous Tl/Ni/P alloys with oxygen. TlNi4(PO4)3 (pale-yellow, orthorhombic, space group Cmc21, a = 6.441(2)A, b = 16.410(4)A, c = 9.624(2)A, Z = 4) crystallizes with a structure closely related to that of NaNi4(PO4)3. Tl4Ni7(PO4)6 (yellow-brown, monoclinic, space group Cm, a = 10.711(1)A, b = 14.275(2)A, c = 6.688(2)A, β = 103.50(2)°, Z = 8) is isotypic with Na4Ni7(PO4)6, and Tl2Ni4(P2O7)(PO4)2 (brown, monoclinic, space group C2/c, a = 10.389(2)A, b = 13.888(16)A, c = 18.198(3)A, β = 103.1(2)°, Z = 8) adopts the K2Ni4(P2O7)(PO4)2 structure. Tl2Ni4(P2O7)(PO4)2 could also be prepared in nearly single phase form by reaction of Tl2CO3, NiO, and (NH4)2HPO4. 
 
 
 
Die Oxidation heterogener Tl/Ni/P-Legierungen — Synthese und Kristallstrukturen der Thallium-Nickel-Phosphate TlNi4(PO4)3, Tl4Ni7(PO4)6 und Tl2Ni4(P2O7)(PO4)2 
 
 
 
Einkristalle der ersten wasserfreien Thallium-Nickel-Phosphate entstanden bei der Umsetzung von Tl/Ni/P-Legierungen mit Sauerstoff . Die Struktur von TlNi4(PO4)3 (blasgelb, orthorhombisch, Raumgruppe Cmc21, a = 6, 441(2)A, b = 16, 410(4)A, c = 9, 624(2)A, Z = 4) ist eng verwandt mit der von NaNi4(PO4)3. Tl4Ni7(PO4)6 (gelbbraun, monoklin, Raumgruppe Cm, a = 10, 711(1)A, b = 14, 275(2)A, c = 6, 688(2)A, β = 103, 50(2)°, Z = 8) ist isotyp mit Na4Ni7(PO4)6, und Tl2Ni4(P2O7)(PO4)2 (braun, monoklin, Raumgruppe C2/c, a = 10, 389(2)A, b = 13, 888(16)A, c = 18, 198(3)A, β = 103, 1(2)°, Z = 8) kristallisiert in der K2Ni4(P2O7)(PO4)2-Struktur. Tl2Ni4(P2O7)(PO4)2 konnte auch nahezu phasenrein durch Umsetzung von Tl2CO3, NiO und (NH4)2HPO4 erhalten werden.
Compressive and flexural properties of hemp fiber reinforced concrete
The compressive and flexural properties of hemp fiber reinforced concretes (FRC) were examined in this paper. Natural hemp fiber was mixed using dry and wet mixing methods to fabricate the FRC. Mechanical properties of the FRC were investigated. The main factors affecting compressive and flexural properties of the FRC materials were evaluated with an orthogonal test design. Fiber content by weight has the largest effect. The method for casting hemp FRC has been optimised. Under the optimum conditions, compressive strength increased by 4 %, flexural strength increased by 9 %, flexural toughness increased by 144 %, and flexural toughness index increased by 214 %.