Tetrapotassium pyrophosphates γ- and δ-K₄P₂O₇

Abstract

The structures of γ-and δ-K 4 P 2 O 7 are solved by X-ray powder diffraction (conventional laboratory X-ray and synchrotron data, respectively), both in hexagonal symmetry (a γ = 5.9645(3) Å, c γ = 14.4972(8) Å, V γ = 446.64(4) Å 3 at 300°C, Z γ = 2, space group P6 3 /mmc; a δ = 10.211 45(7) Å, c δ = 42.6958(4) Å, V δ = 3855.59(7) Å 3 at room temperature, Z δ = 18, space group P6 1 ) with cellsupercell relations a d ≈ a g 3 √ and c δ ≈ 3 c γ . In the experimental conditions, the expected β/γ transition previously announced at 486°C is not observed; the γ-form is stable at least up to the maximum temperature of our measurements (700°C). In the γ-form, similar to the orthorhombic form of Na 4 P 2 O 7 , idealized, the pyrophosphate group is in eclipsed conformation, the K + cations occupying three different coordinations. In the δδ-form, two of the three different [P 2 O 7 ] 4− groups are staggered and one eclipsed, the K + cations occupying 12 independent sites.

Safety Assessment of Phosphoric Acid and Its Salts as Used in Cosmetics

“…31 Other uses include: sequestrant, dispersant, deflocculant, detergent builder, and component of solid or liquid fertilizers. 32 Tetrasodium Pyrophosphate is one of the anticalculus components of most tartar control dentifrices that are marketed. 33 The US Environmental Protection Agency (EPA) has established an exemption from the requirement of a tolerance for residues of Tetrasodium Pyrophosphate when used as an inert ingredient in pesticide formulations applied to growing crops only.…”

“…31 Other uses include: sequestrant, dispersant, deflocculant, detergent builder, and component of solid or liquid fertilizers. 32 Tetrasodium Pyrophosphate is one of the anticalculus components of most tartar control dentifrices that are marketed. 33…”

New Dy3+ Containing Whitlockite for LED Devises

“…The room temperature powder X-ray diffraction (PXRD) patterns of the Ca 9-x Pb x Dy(PO 4 ) 7 were collected on a Termo ARL diffractometer (CuK α1+α2 radiation, reflection geometry, angular range 2θ = 5°-85°, scan step of 0.02. To determine the lattice parameters, Le Bail [17] decomposition was applied using the JANA2006 software [18,19]. Initially, the structure refined by the Rietveld method carried out starting from data [20].…”