The crystal structure of ε-Mg2PO4OH, a synthetic high-temperature polymorph
Abstract
The crystal structure of ε-Mg2PO4OH (Pnma, a = 8.239(1), b = 6.135(1), c = 7.404(1) Å, Z = 4) was solved by direct methods and Fourier syntheses and refined to a final R-value of 0.017 for 637 high-angle reflections. Slightly distorted trans-MgO4(OH)2 octahedra form chains along b by edge-sharing, the chains being connected laterally by pairs of corner-sharing, highly distorted PO4 and MgO4(OH) polyhedra. From steric considerations and a bond-strength calculation, the OH group is found to be essentially unbonded. Morphological study has revealed ten crystal forms. Optical data are: nα = 1.5790, nβ = 1.5830, nγ = 1.5870 (all ± 0.0005 at 589 nm and 22.1 ± 0.1° C); 2VX = 88.1(2)° (from spindle-stage extinction data); X = b, Y = a, Z = c. A phase diagram showing the stability fields of five polymorphs of Mg2PO4OH is presented. The structures of four of these are briefly compared. Infra-red spectra are given for ε- and α-Mg2PO4OH.
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Articles in the same Issue
- The crystal structure of ε-Mg2PO4OH, a synthetic high-temperature polymorph
- The crystal structure of β-Mg2PO4OH, a synthetic hydroxyl analogue of wagnerite
- Structural change of orthorhombic-I tridymite with temperature: A study based on second-order thermal-vibrational parameters
- High-order thermal-motion tensor analyses of tridymite
- The crystal structure of the room-temperature phase of AgTaO3
- The crystal structure of [(CH3)2N(CH2)2(CH2)2O]2NaAg3I6 · 2H2O*
- (Z) phényl-1 diéthylaminocarbonyl-1 aminométhyl-2 cyclopropane (Midalcipran): Etude structurale comparative des variétés Cis, Trans I et Trans II
- Crystal structure and spectra of trans-dichloro-p-chlorobenzoyldi-(2-pyridyl)ketonohydrazono antimony(III)
- Orientational disorder in cubic CsNO2 by neutron powder diffraction
- π-character of C(phenyl) – N(amide) bonds in acetanilides and C(phenyl) – C(keto) bonds in acetophenones
- Crystal structure and chirality of sodium tetrathionate dihydrate, Na2S4O6 · 2H2O
- Crystal structure of bismuth selenochloride, BiSeCl
- Crystal growth and physical properties of l-glutamic acid halides, l-c5H9NO4 · HX (X = Cl, Br, I)
- Third-order elastic constants of cubic NaBrO3, Na3SbS4 · 9H2O and NaH(CH3COO)2
- Crystal structure of FePO4 at 294 and 20 K
- Crystal structure of harstigite, MnCa6Be4[SiO4]2[Si2O7]2(OH)2
- Refinement of the crystal structure of tetraphosphorus decaoxide
- Physikalische Kristallographie“,
