News tagged with hydrogen bonds
Why Does Water Expand When it Cools? A New Explanation
(PhysOrg.com) -- Most of us, when we take our first science classes, learn that when things cool down, they shrink. (When they heat up, we learn, they usually expand.) However, water seems to be the exception ...
Jul 17, 2009 |
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New analysis of the structure of spider silks explains paradox of super-strength
Spiders and silkworms are masters of materials science, but scientists are finally catching up. Silks are among the toughest materials known, stronger and less brittle, pound for pound, than steel. Now scientists ...
Nanotechnology / Nanomaterials
Mar 14, 2010 |
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IBM demonstrates nonoscale 3D patterning technique (w/ Video)
(PhysOrg.com) -- IBM Research in Zurich has demonstrated a new nanoscale patterning technique that could replace electron beam lithography (EBL). The demonstration carved a 1:5 billion scale three-dimensional ...
Apr 23, 2010 |
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Discovery of an Unexpected Boost for Solar Water-Splitting Cells
(PhysOrg.com) -- A research team from Northeastern University and the National Institute of Standards and Technology has discovered, serendipitously, that a residue of a process used to build arrays of titania ...
Nanotechnology / Nanomaterials
Apr 22, 2009 |
5 / 5 (22) |
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Inexpensive catalyst that makes hydrogen gas 10 times faster than natural enzyme
Looking to nature for their muse, researchers have used a common protein to guide the design of a material that can make energy-storing hydrogen gas. The synthetic material works 10 times faster than the original ...
Aug 11, 2011 |
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Water still has a few secrets to tell
(PhysOrg.com) -- We are used to thinking of water as a substance with relatively few secrets left. Its basic structure has been studied by high school students for decades, and water is considered essential ...
Jan 21, 2010 |
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Novel alloy could produce hydrogen fuel from sunlight
Scientists from the University of Kentucky and the University of Louisville have determined that an inexpensive semiconductor material can be "tweaked" to generate hydrogen from water using sunlight.
Aug 30, 2011 |
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Water Motions Revealed (w/ Video)
(PhysOrg.com) -- Gaze into a glass of water, and you're unlikely to see much more than your own reflection. But gaze a little deeper using a microscope -- or, better yet, a series of laser pulses and detectors ...
May 21, 2010 |
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Scientists Observe Liquid Water Below Freezing
(PhysOrg.com) -- Below 0 °C, water turns to ice. But beyond that, or below about -75 °C, the ice may turn back into liquid water. While scientists have previously predicted this phase transition with computer ...
Jun 24, 2009 |
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Scientists investigate how ice melts below freezing due to nanowire's pressure
(PhysOrg.com) -- The many ways in which water differs from other molecules is both a scientific curiosity and an important factor in shaping the Earth. Among water's unique properties are that it expands when ...
Sep 02, 2010 |
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New metal catalyst drives hydrogen fuel reaction forwards and backwards
(PhysOrg.com) -- When it comes to driving hydrogen production, a new catalyst built at Pacific Northwest National Laboratory can do what was previously shown to happen only in nature: store energy in hydrogen and release ...
Feb 16, 2012 |
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World-first to provide building blocks for new nano devices
(PhysOrg.com) -- Scientists at The University of Nottingham have made a major breakthrough that could help shape the future of nanotechnology, by demonstrating for the first time that 3-D molecular structures ...
Nov 23, 2010 |
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Golden pairs: Catalytic dimers of gold atoms make ethylene from methane
(PhysOrg.com) -- Ethylene (ethene, CH2=CH2) is a primary feedstock for chemical industry, and particularly for the production of plastics like polyethylene and polystyrene. Ethylene is currently made by the steam cracking ...
Jan 19, 2010 |
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Disorder is key to nanotube mystery
Scientists often find strange and unexpected things when they look at materials at the nanoscale -- the level of single atoms and molecules. This holds true even for the most common materials, such as water.
Nanotechnology / Nanomaterials
Aug 12, 2011 |
4.9 / 5 (9) |
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Research: Graphene grows better on certain copper crystals
New observations could improve industrial production of high-quality graphene, hastening the era of graphene-based consumer electronics, thanks to University of Illinois engineers.
Nanotechnology / Nanomaterials
Oct 27, 2011 |
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Hydrogen bond
A hydrogen bond is the attractive interaction of a hydrogen atom with an electronegative atom, like nitrogen, oxygen or fluorine (thus the name "hydrogen bond", which must not be confused with a covalent bond to hydrogen). The hydrogen is covalently bonded to another electronegative atom. The energy of a hydrogen bond (typically 5 to 30 kJ/mole) is comparable to that of weak covalent bonds (155 kJ/mol), and a typical covalent bond is only 20 times stronger than an intermolecular hydrogen bond. These bonds can occur between molecules (intermolecularly), or within different parts of a single molecule (intramolecularly). The hydrogen bond is stronger than a van der Waals interaction, but weaker than covalent, or ionic bonds. This type of bond occurs in both inorganic molecules such as water and organic molecules such as DNA.
Intermolecular hydrogen bonding is responsible for the high boiling point of water (100 °C). This is because of the strong hydrogen bond, as opposed to other group 16 hydrides. Intramolecular hydrogen bonding is partly responsible for the secondary, tertiary, and quaternary structures of proteins and nucleic acids.
For more information about Hydrogen bond, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
