Coördination Compounds of Boron Trichloride. V. Relationship of Dipole Moment of Chlorides to Compound Formation.

1947 ◽  
Vol 51 (6) ◽  
pp. 1400-1404 ◽  
Author(s):  
Donald R. Martin
Keyword(s):  
Dipole Moment ◽  
Coordination Compounds ◽  
Compound Formation ◽  
Boron Trichloride ◽  
Relationship Of

Coordination Compounds of Boron Trichloride. I. A Review.

1944 ◽  
Vol 34 (3) ◽  
pp. 461-473 ◽  
Author(s):  
Donald Ray. Martin
Keyword(s):  
Coordination Compounds ◽  
Boron Trichloride

Coordination Compounds of Olefins with Anhydrous Silver Tetrafluoroborate. VI. Complexes with Vinyl Chloride and Vinyl Fluoride

1971 ◽  
Vol 49 (9) ◽  
pp. 1323-1327 ◽  
Author(s):  
H. W. Quinn ◽  
R. L. Vangilder
Keyword(s):  
Dipole Moment ◽  
Vinyl Chloride ◽  
Coordination Compounds ◽  
Silver Ion ◽  
Permanent Dipole Moment ◽  
Vinyl Fluoride ◽  
Lower Stability ◽  
The Stability

The stability of the complexes AgBF4•2 vinyl chloride and AgBF4•2 vinyl fluoride has been determined and compared with that of AgBF4•2 propylene. The much lower stability of the halo-olefin complexes has been attributed partly to weaker interaction of these less basic olefins with the silver ion and partly to configurational restrictions imposed upon the complexed halo-olefin molecules as a result of their higher permanent dipole moment.

TWO-COMPONENT SYSTEMS INVOLVING COMPOUND FORMATION

1931 ◽  
Vol 5 (4) ◽  
pp. 436-441 ◽  
Author(s):  
J. Russell ◽  
O. Maass
Keyword(s):  
Hydrogen Chloride ◽  
Methyl Alcohol ◽  
Ethyl Ether ◽  
Compound Formation ◽  
Gaseous State ◽  
Temperature Range ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
Relationship Of

The two-component systems ethyl ether-hydrogen chloride and methyl alcohol-hydrogen chloride have been examined in the gaseous state, and from the pressure-volume-temperature relationship of the binary mixture evidence is adduced of the existence of compound formation. The heats of reaction appear to be constant in the temperature range investigated, and are 5400 calories for the ether hydrochloride, and 9200 calories for the alcohol hydrochloride. The pressure-volume-temperature data for ethyl ether, methyl alcohol and ethyl alcohol are given over the temperature range 50–200 °C., and over the pressure range below one atmosphere.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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