Crystal structure of the cyclotetraphosphate Ca₂[P₄O₁₂] · 4 H₂O

Abstract

Ca2[P4O12] · 4 H2O crystallizes in the monoclinic space group P21/n, a = 7.668, b = 12.895, c = 7.144 Å, β 107.00°, Dx = 2.28 g · cm−3, Z = 2. In the structure there are ringlike anions, which are composed of 4 PO4 tetrahedra connected by oxygen bridges. The Ca2+ are surrounded by 7 oxygen atoms. Each two cation polyhedra are connected by a common edge to pairs which are isolated from one another. The water molecules form hydrogen bridges with one another and with the anion rings.

Synthesis, Crystal Structure and Vibrational Spectra of Barium Cyclotetraphosphate Hydrate Ba2(P4O12)∙3.5H2O

“…In calcium cyclotetraphosphate tetrahydrate, Ca 2 (P 4 O 12 )∙4H 2 O 4, the calcium ions form an arrangement similar to cubic diamond, and therefore Ca 2 (P 4 O 12 )∙4H 2 O has an unit cell with less than a half of the c axis found in the barium compound.…”

“…An indexed powder diffraction pattern of a compound of similar composition was already given 2 which can now be attributed to this cyclotetraphosphate. The targeted alkaline earth phosphates attract interest in materials science due to the possibility of doping them with divalent or trivalent rare earth ions to produce efficient fluorescent materials 3.So far, of the alkaline earth cyclotetraphosphates only Ca 2 (P 4 O 12 )∙4H 2 O 4 and strontium cyclotetraphosphate Sr 2 (P 4 O 12 )∙6H 2 O 5 have been successfully characterized. In this contribution the solution of the crystal structure of the possible precursor compound for condensed barium phosphates Ba 2 (PO 3 ) 4 ∙3.5H 2 O including a thermogravimetric study will be presented.…”

Four New Sb‐based Orthophosphates: Cation Regulation to Investigate Diversified Structural Architecture

“…[11][12][13][14][15][16] In addition, the structural flexibility can also be improved by introducing metal elements with strong covalency. Normally, phosphates contain only one kind of anion, such as LiHgPO 4 , Li 2 ABi(PO 4 ) 2 (A=K, Rb, and Cs) and KMg(H 2 O)PO 4 with isolated [PO 4 ] tetrahedral, [17][18][19] A 3 BBi(P 2 O 7 ) 2 (A=Rb, Cs; B=Pb, Ba) and M 4 Mg 4 (P 2 O 7 ) 3 (M=K, Rb) with isolated [P 2 O 7 ] dimers, [20][21][22] Ba 5 P 6 O 20 and AAl 3 P 6 O 20 (A=Rb, Cs) with isolated [P 3 O 10 ] trimers, [10b,23] isolated [P 3 O 9 ] rings for KMg(P 3 O 9 ) and BaNaP 3 O 9 , [24,25] [P 4 O 12 ] rings for Ca 2 (P 4 O 12 ) • 4H 2 O, [26] [P 6 O 18 ] rings for Cs 2 Mg 2 P 6 O 18 [27] as well as RbBa 2 (PO 3 ) 5 , β-Cd(PO 3 ) 2 with infinite [PO 3 ] ∞ chains. [10a,28] There are some exceptions for phosphates with mixed PÀ O anions, such as Pb 2 Cd 3 (PO 4 ) 2 (P 2 O 7 ), [29] Na 4 Mg 3 (PO 4 ) 2 P 2 O 7 , [30] and LiMg 3 (PO 4 )P 2 O 7 , etc.…”