Synthesis, Crystal Structure, and Vibrational Spectra of Ca₄P₆O₁₉ (Trömelite) ‐ a catena‐Hexaphosphate

Abstract

The catena–hexaphosphate Ca4P6O19 (Trömelite) was obtained by the reaction of calcium oxide with H3PO3 in a tube furnace at a temperature of 900 °C and crystallizes triclinic (space group $P{\bar 1}$, Z = 2, a = 685.70(9) pm, b = 915.47(12) pm, c = 1282.25(17) pm, α = 109.602(10)°, β = 99.778(10)°, γ = 91.917(10)°, V = 743.70(17)·106 pm3). According to the powder diffraction data of Ca4P6O19 a Rietveld refinement of the lattice constants was performed; this confirmed the single–crystal data. Trömelite contains chains of six condensed corner‐sharing PO4 tetrahedra with the Ca atoms in the voids of the resulting structure. IR and Raman data of Trömelite are also presented.

Structure of Na2O–CaO–P2O5–SiO2 Glass–Ceramics with Multimodal Porosity

“…For the heat‐treated sample (b), the band at 860 cm −1 has disappeared and those at ∼625 and ∼945 cm −1 have significantly narrowed and are shifted to ∼590 and ∼990 cm −1 , compared with the spectrum of sample (a). The appearance of the bands at 911, ∼700, and 531 cm −1 for the heat‐treated sample indicates that these bands are due to the formation of the calcium phosphate and sodium–calcium silicate crystal phases, respectively, and agree well with previous results 20,22 . Comparing the spectra of samples (b, c), it can be seen that the peaks at 527 and 911 cm −1 are missing from the spectra of the chemically leached sample.…”

“…For sample (b), the peaks at 450, 525, and 620 cm −1 arise from the formation of the crystalline phases in this glass composition 18,19 . The peaks at 525 and 620 cm −1 arise either from the Na 2 Ca 2 Si 3 O 9 or from the Na 2 CaSi 3 O 8 phase, 18 while the peak at 450 cm −1 most likely arises from the calcium phosphate phase 20 . The leaching removes these sodium‐containing crystalline phases, as can be seen by the disappearance of the peaks at 620 and 525 cm −1 from the spectrum of sample (c), corresponding to the absence of some of the XRD peaks in Fig.…”

Das erste Borosulfat K5[B(SO4)4]

“…Unseres Wissens gibt es kein Beispiel für eine solche Anionentopologie in der Sulfat‐ oder Phosphatchemie. Oligophosphate bilden wie die Sulfate lineare Anionen, wie in Trömelit (Ca 4 [P 6 O 19 ]),8 allerdings enthalten die Borophosphate M 6 [B(PO 4 ) 4 ][PO 4 ] (M=Pb, Sr) das topologisch identische [B(PO 4 ) 4 ]‐Anion 9. Darüber hinaus sind in unter Normaldruck hergestellten Verbindungen Borattetraeder eher selten über sämtliche Ecken mit weiteren Tetraedern verknüpft.…”

Sn[B2O3F2]—The First Tin Fluorooxoborate as Possible NLO Material

“…In the course of our systematic investigations of silicate‐analogous materials we also focus on inorganic fluoro‐derivatives of oxo‐anions like phosphates, borates and tungstates . Recently, we discovered the very first alkaline‐earth fluorooxoborate Ba[B 4 O 6 F 2 ] which crystallizes centrosymmetrically—in contrast to a prediction—and could be doped with Eu 2+ to show efficient ultraviolet luminescence proving the weak coordinative force expected in such materials; here a simple spherical cation lead to a centrosymmetric structure.…”