Premium
Two New, Metastable Polymorphs of Lithium Pyrophosphate Li 4 P 2 O 7
Author(s) -
Raguž Branimir,
Wittich Knut,
Glaum Robert
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201801100
Subject(s) - chemistry , triclinic crystal system , crystallography , trigonal crystal system , rietveld refinement , powder diffraction , crystal structure , lithium (medication) , x ray crystallography , diffraction , medicine , endocrinology , physics , optics
By quenching a melt of Li 4 P 2 O 7 two new, thermodynamically metastable polymorphs are obtained as biphasic mixtures. The crystal structure of one polymorph was determined from single‐crystal X ‐ray diffraction data {Li 4 P 2 O 7 ‐trig*: colorless, trigonal, P 3 2 12 (no. 153), Z = 3, a = 5.1699(2) Å, c = 18.9722(8) Å, 60 parameters, R 1 = 0.018, wR 2 = 0.051, 1265 unique reflections with F o > 4 σ (F o )}. For the second polymorph a structure model was derived, using direct space methods followed by Rietveld refinement {Li 4 P 2 O 7 ‐pseudomono*: P 1 , a = 7.88468(5) Å, b = 10.30394(6) Å, c = 7.54581(4) Å, α = 89.8142(6)°, β = 115.26(2)°, γ = 90.2015(5)°, R I = 7.62}. 31 P‐MAS‐NMR measurements show δ iso = –2.9 ppm for Li 4 P 2 O 7 ‐pseudomono* and δ iso = –6.6 ppm for the trigonal polymorph. Substitution of about 10 % lithium by copper(I) is possible in the trigonal as well as in the long known triclinic polymorph as is evidenced by the results of SXRD, XRPD, and 31 P‐MAS‐NMR measurements.