Unusual crystallization behaviour

Woodard, G. D.; McCrone, Walter C.

doi:10.1107/s002188987501062x

Cited by 14 publications

(13 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…H20(o), we would add that the order of stability, which we have observed, is the opposite of that reported in the literature (cf Pascal, 1966); Dufet (1887) noticed that the introduction of the bihydrate in his laboratory affected the stability of the monohydrate (which was introduced in our laboratory after the bihydrate). These observations could be related to similar phenomena reported by Woodard & McCrone (1975).…”

supporting

confidence: 70%

Hydrogen bonding in the crystalline state. Structure of NaH₂PO₄.H₂O (orthorhombic phase), and crystal chemistry of the NaH₂PO₄.nH₂O series

Catti¹,

Ferraris²

1976

Acta Crystallogr Sect B

View full text Add to dashboard Cite

NaH2PO4. H20, orthorhombic phase, crystallizes in space group Pna21, with a = 7"616 (5), b = 7-899 (3), c=7.382 (2) /~, Z=4. The structure was solved (direct methods) and refined anisotropically (least squares, R= 0.034) with 678 reflexions measured on a diffractometer with Mo K~ radiation. H atoms were located on difference maps, but were not refined. Pnam pseudo-symmetry explains the formation of (001) twins by merohedry.[001] chains of Na coordination octahedra sharing edges develop in pseudotetragonal channels present in the framework of P tetrahedra; these are tied by medium-strength acidic hydrogen bonds. Water hydrogen bonds are weak. Bond-strength/bond-length correlations are discussed. Chains of Na polyhedra are present in all structures of the series NaH2PO4. nH20; their linking accounts for the decreasing packing density with increasing hydration. The close similarity of structures of the bihydrated and of the two monohydrated forms is analysed, and a mechanism is proposed for the solidstate reaction NaH2PO4.2H20 .~-NaH2PO4. H20 + H20.

show abstract

supporting

confidence: 70%

Hydrogen bonding in the crystalline state. Structure of NaH₂PO₄.H₂O (orthorhombic phase), and crystal chemistry of the NaH₂PO₄.nH₂O series

Catti¹,

Ferraris²

1976

Acta Crystallogr Sect B

View full text Add to dashboard Cite

show abstract

“…Nevertheless, our work may shed light on the strange realm of di-or polymorphism of crystals discussed by Woodard & McCrone (1975) …”

Section: Methodsmentioning

confidence: 99%

Structure of the unstable monoclinic 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose

Czugler¹,

Kàlmán²,

Kovács³

et al. 1981

Acta Crystallogr Sect B

View full text Add to dashboard Cite

The unstable A form of 1,2,3,5-tetra-O-acetyl-fl-Dribofuranose, C13H1809 (m.p. = 330-331 K), crystallizes in the monoclinic system, a = 12.649 (2), b = 5.582 (2), c = 11.078(2) A,/3 = 97.92(1) °, space group P2~, Z = 2, D e = 1.364 Mg m -3. Final R = 0.045 for 1142 reflexions. To shed light on the spontaneous and irreversible transition of form A into * Dedicated to Professor Geza Schay (first director of CRIC) on his 80th birthday. the stable orthorhombic form B (m.p. 358 K) the present structure determination of A is compared with that of B reported by James & Stevens [Cryst. Struct. Commun. (1973), 2, 609-612] and Poppleton ]Acta Cryst. (1976), B32, 2702-2705]. Neither the bonding of the molecules nor the puckering of the furanose rings reveals significant differences. However, two of the four acetyl moieties exhibit torsional parameters [C(4) IntroductionThe structural dimorphism of 1,2,3,5-tetra-O-acetylfl-D-ribofuranose (I) was discovered when Zinner (1950) found that the title compound, obtained by direct acetylation of D-ribose, showed a considerably higher melting point (355 K) than had been found by Howard, Lythgoe & Todd (1947) and Bredereck & Hoepfner (1948) (331 and 329 K, respectively). Davoll, Brown & Visser (1952) also prepared crystals which melted in the range 329-331 K, but repetition of the procedure described by Bredereck & Hoepfner (1948) yielded a sample melting at 358 K. The identical molecular structure of the higher-melting crystals (hereafter B) with that of the lower-melting product (hereafter A) was proved by preparative methods. When crystals of A were exposed to the air in a laboratory inoculated with B their melting points rose to 358 K while the crystals rapidly became opaque and A could not be prepared thereafter. Their structural dimorphism was suggested by Farrar (1952) who pointed out that both forms exhibit the same specific rotation in chloroform. Patterson & Groshens (1954), who determined the lattice parameters and space group of both crystals (A: monoclinic P2~, Z = 2, B: orthorhombic P2~2121, Z = 4), corroborated Farrar's conclusions. They also observed rapid and irreversible phase transformations of A into B catalysed by the presence of B crystals. Since then, no comparative structural studies of A and B have been reported, presumably because of fruitless attempts to prepare the unstable A (Poppleton, 1976). Accordingly, the crystal structure of B could only be determined to date (James & Stevens, 1973;Poppleton, 1976). IAcO OAcRecently, whilst preparing ribofuranosyl derivatives, we have synthesized the title compound and obtained crystals which melt at 331 K. Its optical rotation in chloroform was identical to that of the higher melting B. Since we have invariably grown A in several experiments it seemed worthwhile to determine its crystal structure by X-ray diffraction and compare it with that of B. ExperimentalThe title compound was prepared according to Guthrie & Smith (1968). Both base-and acid-catalysed acetylation gave the same product; colourless, ...

show abstract

“…2 Although much work has been carried out on polymorphs, they are still rather mysterious in some aspects, as their appearance can be notoriously difficult to control (with reports of polymorphs 'disappearing' from a laboratory altogether). 1,3,4 It is also exceedingly difficult to predict whether a compound will display polymorphism or not, and if it does, what the nature of the different crystal packing and motifs will be. For example, 12 polymorphs of N,N'dithiobisphthalimide 5 have thus far been discovered, whereas the same rigorous search for polymorphs of triphenylsilanol yielded just one.…”

Section: Introductionmentioning

confidence: 99%

A new polymorph of terpyridine: variable temperature X-ray diffraction studies and solid state photophysical properties

et al. 2005

View full text Add to dashboard Cite

Unusual crystallization behaviour

Cited by 14 publications

References 7 publications

Hydrogen bonding in the crystalline state. Structure of NaH₂PO₄.H₂O (orthorhombic phase), and crystal chemistry of the NaH₂PO₄.nH₂O series

Hydrogen bonding in the crystalline state. Structure of NaH₂PO₄.H₂O (orthorhombic phase), and crystal chemistry of the NaH₂PO₄.nH₂O series

Structure of the unstable monoclinic 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose

A new polymorph of terpyridine: variable temperature X-ray diffraction studies and solid state photophysical properties

Contact Info

Product

Resources

About

Unusual crystallization behaviour

Cited by 14 publications

References 7 publications

Hydrogen bonding in the crystalline state. Structure of NaH2PO4.H2O (orthorhombic phase), and crystal chemistry of the NaH2PO4.nH2O series

Hydrogen bonding in the crystalline state. Structure of NaH2PO4.H2O (orthorhombic phase), and crystal chemistry of the NaH2PO4.nH2O series

Structure of the unstable monoclinic 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose

A new polymorph of terpyridine: variable temperature X-ray diffraction studies and solid state photophysical properties

Contact Info

Product

Resources

About

Hydrogen bonding in the crystalline state. Structure of NaH₂PO₄.H₂O (orthorhombic phase), and crystal chemistry of the NaH₂PO₄.nH₂O series

Hydrogen bonding in the crystalline state. Structure of NaH₂PO₄.H₂O (orthorhombic phase), and crystal chemistry of the NaH₂PO₄.nH₂O series