Einige Gesichtspunkte zu den Wandlungen der Oxydhydrate

Fricke, R.; Engelhard, F.; Havestadt, L.; Humme, H.; Meyring, K.

doi:10.1007/bf01422729

Cited by 32 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This bayerite (A1203 • 3H20), to the properties of which we shall refer later, also belongs to the -series of Haber, since it produces cubic -oxide on complete extraction of water. It is metastable at room temperature in contrast to gibbsite (hydrargillite) (9,10,11,17), but stable in comparison with bohmite (3,20,24). It is probably identical with the substance designated as ß-1203•3 20 by Edwards and Tosterud.…”

mentioning

confidence: 93%

“…3H20), to the properties of which we shall refer later, also belongs to the y-series of Haber, since it produces cubic y-oxide on complete extraction of water. It is metastable a t room temperature in contrast to gibbsite (hydrargillite) (9,10,11,17), but stable in comparison with bohmite (3, 20, 24). It is probably identical with the substance designated as p-Al203.3H~O by Edwards and Tosterud. It is quite evident from the photographs of Weiser and Milligan that their preparations, made "according to Huttig," cannot be mixtures of bohmite and gibbsite; this may also be seen from a comparison of the positions of the lines of the alleged "6-AlzOa.xHzO" (bohmite) and of gibbsite with the positions of the lines of the preparations according to Huttig.…”

mentioning

confidence: 97%

“…Weiser and Milligan (31) made further preparations according to the directions of Hüttig and Kostelitz (21), and from the x-ray photographs obtained from these preparations they arrived at the conclusion that, in the case of the preparations K/, K/, K2, K3, and L3, according to Hüttig, there was no definite compound, but a mixture of -1203• 20 and gibbsite. In contrast, Hüttig and his collaborators (21,23) ascribe these preparations to the "isomers of hydrargillite" first discovered by Bohm (3) and later carefully investigated by Fricke (9,10,11), which, in accordance with a proposal made by Fricke (9), because of the precipitation of the substance when alumina is prepared by K. J. Bayer's process, is now termed bayerite in European literature. This bayerite (A1203 • 3H20), to the properties of which we shall refer later, also belongs to the -series of Haber, since it produces cubic -oxide on complete extraction of water.…”

mentioning

confidence: 98%

“…Provided the temperature is the same, a slow precipitation is then favorable for the formation of gibbsite, and rapid precipitation for bayerite (9). More accurate details for the production of the two alumina hydrates in this manner, which is important from a technical point of view, may be found in other articles (11,13,17).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Böhmite and Bayerite

Lehl¹

1936

J. Phys. Chem.

View full text Add to dashboard Cite

An article by Weiser and Milligan (31),• entitled "X-ray Studies on the Hydrous Oxides. I. Alumina," appeared in this Journal in December, 1932; from the x-ray photographs of preparations made in various ways the authors arrived at the following conclusions: " .. . there are two alumina hydrates: (1) gibbsite,A1203• 3H20, both natural and artificial, and (2) diaspore, A1203-H20. Precipitated alumina aged at 100°has been found by x-ray diffraction methods to be a new form of alumina which has been termed -1203, with adsorbed water." In reply to this article Edwards and Tosterud (8) refer to the existence of an -1203• 20 which differed from diaspore (to which they gave the designation ß-1203• 20;cf. in what follows the designation of Haber ( 18)). Furthermore there was described a ß-1203•3 20, which differed from gibbsite (hydrargillite, or -1203•3H20, according to Edwards and Tosterud). The object of this communication is to draw attention to some publications which, although not mentioned by Weiser and Milligan or by Edwards and Tosterud, nevertheless bear on the matter. Proof will, moreover, be brought to show that the preparation which Weiser and Milligan termed "a mixture of -1203 and gibbsite" has likewise given a distinctivex-ray photograph, according to the radiograms by these authors, which belongs to a definite trihydrate, namely, bayerite, or ¡3-trihydrate, according to Edwards and Tosterud (8). BOHMITEBohm and Niclassen (4), as well as Fricke and We ver ( 16), had already shown in 1924 that at higher temperatures (as, for instance, approximately 100°C.) aluminum hydroxide precipitated from a solution of aluminum sulfate with aqueous ammonia gave a hitherto unknown x-ray diagram.A year later Bohm published the reproduction of an x-ray photograph which showed the lattice of a very pure aluminum hydroxide having the composition A1203 • II20 from Les Baux. This lattice of very definite form was different from those of diaspore, the trihydrate, and the oxide of aluminum, although the film shows the same lines as those which Bohm and Fricke had obtained from the preparations precipitated at a higher temperature.

show abstract

mentioning

confidence: 93%

mentioning

confidence: 97%

mentioning

confidence: 98%

mentioning

confidence: 99%

See 2 more Smart Citations

Böhmite and Bayerite

Lehl¹

1936

J. Phys. Chem.

View full text Add to dashboard Cite

show abstract

Aluminium, Gallium, Indium and Thallium

2016

Hydrolysis of Metal Ions

View full text Add to dashboard Cite

Aktive Zustände der festen Materie und ihre Bedeutung für die anorganische Chemie 33. Mitt. über aktive Stoffe

Fricke¹

1938

Angewandte Chemie

View full text Add to dashboard Cite

Aktive Zusthde der festen Materie und ihre Bedeutung fiir die anorganische Chemie*) 33. Mitt. iiber aktive Stoffel) V o n P r o f . D r . R. F R I C K E I n ha1 t : Einleitung -Zwtcand und Warmeinhalt aktiver jester Stojje: Zerteilungegrd, a b o r a t o y i fii A n o r g u n * ' l t e m i e Stiir26ngen des Kristallgitterbaues, Gitterdehnungen, Ainorpher Zustand -Chemisehe Awm'rkungen der erhdhten Aktivitat : Zeraetzungadrzdcke von Oxyden, Hydroxyden W W . , Oxydations -RedzGkticns -Gleichgewiehte uber fein aerteilten and kompakten Metallen, Chemisehe Reaktwnen im festen Zuetand.7'. H . S t u t t g a r l . filngeg. 3.Okl'lder 1930Einleitung .1. Der Begriff der chemischen Aktivitat entstammt urspriinglich experimentellen Erfahrungen uber die Reaktionsfiihigkeit. Schon friihzeitig wurde erkannt, daB die Reaktionsfahigkeit eines festen Karpers nicht nur vom chemischen Charakter, sondern auch vom Zerteilungsgrad, also von der OberflachengroBe abhangt. Das Studium der mit dem Zerteilungsgrad zusammenhangenden Erscheinungen erhielt einen machtigen Impuls durch die Entwicklung bestimmter Zweige der physikalischen Chemie sowie der Kolloidchemie.Die zum Teil im Zusammenhang hiermit sich entwickelnde h h r e von der heterogenen Katalyse betrachtete denn auch zuerst als die wesentlichste Eigenschaft eines guten Katalysators den kolloiden Zerteilungszustand. Die spatere Entwicklung der Katalysatorforschung (Mittasch, Taylor, Schwab u. a.) zeigte aber, da13, abgesehen von der Art des chemischen Stoffes und von seinem Zerteilungszustand, auch noch andere Eigenschaften fiir die katalytische Aktivitat von Bedeutung sein mussen. Das auaerordentliche Anwachsen der Forschung uber heterogene Katalyse im Verein mit der Entwicklung der chemischen GroSindustrie in der gleichen Richtung fiihrte dann in neuester Zeit dam, da13 vielfach die Begriffe ,,aktiv" und ,,katalytisch aktiv" bewuflt oder unbewuflt gleich gesetzt werden.Wir wollen den Begriff des aktiven Zustandes fester Stoffe weiter fassen, indem wir darunter einfach einen Zustand mitgegeniiber dem normalenerhiihtem Inhalt an Gesamtenergie verstehen. Ein derartiger aktiverZustand kann die verschiedensten Ursachen haben. Zunachst kann man hier hineinrechnen die metastabilen allotropen Modifikationen. Seit der Einfiihrung des Debye-Schewer-Verfahrens der Rontgenaufnahmen in die chemische Forschung wissen wir, daB die Zahl der Allotropieerscheinungen eine auBerordentlich vie1 graere ist, als friiher angenommen wurde. Insbes. bei den Oxyden und Hydroxyden ergab sich eine groBe Zahl neuer, bisher unbekannter Kristallarten ( B mdisch, Bohm, Feithecht, Fricke, Huttig, Weiser u. Milligan u. a.). Ein oberblick iiber die bisher bekannten Kristallarten einiger Oxyde und Hydroxyde findet sich in Tabelle 1 und 2. Die Pfeile geben in Tabelle 1 die Richtungen abnehmender StabiLitat unter Normalbedingungen, in Tabelle 2 die *) Zusammenfassender Vortrag auf der auswartigen Tagung der Deutschen Chemischen Gesellschaft am 18. September 1938 an-IaDlich der 95. Versammlung Deutscher Naturforscher und ...

show abstract

Einige Gesichtspunkte zu den Wandlungen der Oxydhydrate

Cited by 32 publications

References 0 publications

Böhmite and Bayerite

Böhmite and Bayerite

Aluminium, Gallium, Indium and Thallium

Aktive Zustände der festen Materie und ihre Bedeutung für die anorganische Chemie 33. Mitt. über aktive Stoffe

Contact Info

Product

Resources

About