The cationic complex in the title compound, [Ir(C9H7N2)2(C12H8N2)]PF6, comprises two phenylpyrazole (ppz) cyclometallating ligands and one 1,10-phenanthroline (phen) ancillary ligand. The asymmetric unit consists of one [Ir(ppz)2(phen)]+ cation and one [PF6]− counter-ion. The central IrIII ion is six-coordinated by two N atoms and two C atoms from the two ppz ligands as well as by two N atoms from the phen ligand within a distorted octahedral C2N4 coordination set. In the crystal structure, the [Ir(ppz)2(phen)]+ cations and PF6− counter-ions are connected with each other through weak intermolecular C—H...F hydrogen bonds. Additional C—H...π interactions between the rings of neighbouring cations consolidate the three-dimensional network. Electron density associated with additional disordered solvent molecules inside cavities of the structure was removed with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s). The title compound has a different space-group symmetry (C2/c) from its solvatomorph (P21/c) comprising 1.5CH2Cl2 solvent molecules per ion pair.

In small-molecule single-crystal structure determination, we now have at our disposal an inspiring range of fantastic diffractometers with better, brighter sources, and faster, more sensitive detectors. Faster and more powerful computers provide integrated tools and software with impressive graphical user interfaces. Yet these tools can lead to the temptation not to check the work thoroughly and one can too easily overlook tell-tale signs that something might be amiss in a structure determination; validation with checkCIF is not always revealing. This article aims to encourage practitioners, young and seasoned, by enhancing their structure-determination toolboxes with a selection tips and tricks on recognizing and handling aspects that one should constantly be aware of. Topics include a pitfall when setting up data collections, the usefulness of reciprocal lattice layer images, processing twinned data, tips for disorder modelling and the use of restraints, ensuring hydrogen atoms are added to a model correctly, validation beyond checkCIF, and the derivation and interpretation of the final results.

Crystals of the rare earth metal polytelluride LaTe1.82(1), namely, lanthanum telluride (1/1.8), have been grown by molten alkali halide flux reactions and vapour-assisted crystallization with iodine. The two-dimensionally incommensurately modulated crystal structure has been investigated by X-ray diffraction experiments. In contrast to the tetra­gonal average structure with unit-cell dimensions of a = 4.4996 (5) and c = 9.179 (1) Å at 296 (1) K, which was solved and refined in the space group P4/nmm (No. 129), the satellite reflections are not compatible with a tetra­gonal symmetry but enforce a symmetry reduction. Possible space groups have been derived by group–subgroup relationships and by consideration of previous reports on similar rare earth metal polychalcogenide structures. Two structural models in the ortho­rhom­bic superspace group, i.e. Pmmn(α,β,1 over 2)000(−α,β,1 over 2)000 (No. 59.2.51.39) and Pm21n(α,β,1 over 2)000(−α,β,1 over 2)000 (No. 31.2.51.35), with modulation wave vectors q1 = αa* + βb* + 1 over 2c* and q2 = −αa* + βb* + 1 over 2c* [α = 0.272 (1) and β = 0.314 (1)], have been established and evaluated against each other. The modulation describes the distribution of defects in the planar [Te] layer, coupled to a displacive modulation due to the formation of different Te anions. The bonding situation in the planar [Te] layer and the different Te anion species have been investigated by density functional theory (DFT) methods and an electron localizability indicator (ELI-D)-based bonding analysis on three different approximants. The temperature-dependent electrical resistance revealed a semiconducting behaviour with an estimated band gap of 0.17 eV.

During evaporation of natural and synthetic K–Mg–Cl brines, the formation of almost square plate-like crystals of potassium carnallite (potassium chloride magnesium dichloride hexa­hydrate) was observed. A single-crystal structure analysis revealed a monoclinic cell [a = 9.251 (2), b = 9.516 (2), c = 13.217 (4) Å, β = 90.06 (2)° and space group C2/c]. The structure is isomorphous with other carnallite-type com­pounds, such as NH4Cl·MgCl2·6H2O. Until now, natural and synthetic carnallite, KCl·MgCl2·6H2O, was only known in its ortho­rhom­bic form [a = 16.0780 (3), b = 22.3850 (5), c = 9.5422 (2) Å and space group Pnna].

A new polymorph (form II) is reported for the 1:1 dimethyl sulfoxide solvate of 2,3,5,6-tetra­fluoro-1,4-di­iodo­benzene (TFDIB·DMSO or C6F4I2·C2H6SO). The structure is similar to that of a previously reported polymorph (form I) [Britton (2003). Acta Cryst. E59, o1332–o1333], containing layers of TFDIB mol­ecules with DMSO mol­ecules between, accepting I⋯O halogen bonds from two TFDIB mol­ecules. Re-examination of form I over the temperature range 300–120 K shows that it undergoes a phase transformation around 220 K, where the DMSO mol­ecules undergo re-orientation and become ordered. The unit cell expands by ca 0.5 Å along the c axis and contracts by ca 1.0 Å along the a axis, and the space-group symmetry is reduced from Pnma to P212121. Refinement of form I against data collected at 220 K captures the (average) structure of the crystal prior to the phase transformation, with the DMSO mol­ecules showing four distinct disorder com­ponents, corresponding to an overlay of the 297 and 120 K structures. Assessment of the inter­molecular inter­action energies using the PIXEL method indicates that the various orientations of the DMSO mol­ecules have very similar total inter­action energies with the molecules of the TFDIB framework. The phase transformation is driven by inter­actions between DMSO mol­ecules, whereby re-orientation at lower temperature yields significantly closer and more stabilizing inter­actions between neighbouring DMSO mol­ecules, which lock in an ordered arrangement along the shortened a axis.

The application of groupoids to modular crystal structures is presented.

A method is adapted to generate a full rank realization of an abstract regular polyhedron with automorphism group H3.

Structure-mining finds and returns the best-fit structures from structural databases given a measured pair distribution function data set. Using databases and heuristics for automation it has the potential to save experimenters a large amount of time as they explore candidate structures from the literature.

To describe multiple Bragg reflection from a thick, ideally imperfect crystal, the transport equations are reformulated in three-dimensional phase space and solved by spectral collocation in the depth coordinate. Example solutions illustrate the orientational spread of multiply reflected rays and the distortion of rocking curves, especially for finite detectors.

The inversion of X-ray reflectivity to reveal the topography of a one-dimensional interface is evaluated through model calculations.

Parents of students at Miramonte Elementary School escort children out of school on Feb. 6, 2012.; Credit: Grant Slater/KPCC

A lawyer representing 58 students who settled a lawsuit related to the Miramonte sex abuse scandal two years ago said his clients are owed more money because another group of students who settled their lawsuit last fall for $139 million may be paid more, and that violates the terms of the first group's settlement. 

A total of more than 100 students and parents sued the district after former Miramonte Elementary School teacher Mark Berndt was charged with 23 counts of committing lewd acts, including feeding students cookies laced with semen. Berndt is serving 25 years in prison. 

Attorney Paul Kiesel's clients were among the first group of students who settled in 2013 for $470,000 each, a total of $30 million. In a claim submitted to the district on Feb. 6, Keisel argues that settlement prohibits other students from receiving more than his clients.

The settlement for Kiesel's group states that it is the intent of the parties that any future Miramonte-related settlements pay less per plaintiff than the $470,000 figure.  In the case of the suit that was settled for $139 million, a judge is deciding how much each plaintiff will receive; it is expected that some of the students will receive more than $470,000.

Kiesel's complaint seeks the difference between what his clients were paid and the highest amount awarded to students in the second group.

The $139 million settlement was the largest of its kind in Los Angeles Unified School District history. 

If Kiesel's clients prevail, the district's overall tab for the Miramonte case could significantly increase from the $170 million in settlements awarded so far. 

The school district has yet to respond to the claim and declined to comment for this story. 

Kiesel would not discuss the claim in greater detail, but attorney Raymond Boucher, who also represented students in the initial settlement, characterized its language limiting the size of future settlements as a "fairness clause.

"We are talking about a number of young children and you want to make sure they are all treated fairly and equally," Boucher told KPCC. 

Attorney Vince William Finaldi, who represented some of the students in the group that settled for $139 million last November, argued that the earlier settlement would need to include a "most favored nation clause" to prevail in court. 

"It needs to have two elements," Finaldi said. "The first element is a statement by the settling party that 'we agree not to pay anyone else more than X amount.' It also needs a second clause which states, 'in the event we do pay someone more than X amount, then we'll pay you Y amount," Finaldi said. 

The settlement for Kiesel and Boucher's clients does not include language stipulating what would happen if a future settlement pays out more money per plaintiff.

If L.A. Unified rejects Kiesel's claim, then he could ask a mediator or a court to resolve the dispute.

This content is from Southern California Public Radio. View the original story at SCPR.org.

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The Maya of Central America are thought to have been a kinder, gentler civilization, especially compared to the Aztecs of Mexico. At the peak of Mayan culture some 1,500 years ago, warfare seemed ritualistic, designed to extort ransom for captive royalty or to subjugate rival dynasties, with limited impact on the surrounding population. Only later, archeologists thought, did increasing drought and climate change lead to total warfare -- cities and dynasties were wiped off the map in so-called termination events -- and the collapse of the lowland Maya civilization around 1,000 A.D. (or C.E., current era). New evidence unearthed by National Science Foundation-funded researchers call all this into question, suggesting that the Maya engaged in scorched-earth military campaigns -- a strategy that aims to destroy anything of use, including cropland -- even at the height of their civilization, a time of prosperity and artistic sophistication. The finding also indicates that this increase in warfare, possibly associated with climate change and resource scarcity, was not the cause of the disintegration of the lowland Maya civilization.

Image credit: Francisco Estrada-Belli/Tulane

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The molecular mechanism used by many bacteria to kill neighboring cells has redundancy built into its genetic makeup, which could allow for the mechanism to be expressed in different environments, say researchers at Penn State and the University of Wisconsin-Madison. Their new study provides insights into the molecular mechanisms of competition among bacteria. "Many organisms, including humans, acquire bacteria from their environment," said Tim Miyashiro, a biochemist and molecular biologist at Penn State and the leader of the research team. "These bacteria can contribute to functions within the host organism, like how our gut bacteria help us digest food. We're interested in the interactions among bacteria cells, and between bacteria and their hosts, to better understand these mutually beneficial symbiotic relationships." Cells of the bioluminescent bacteria Vibrio fisheri take up residence in the light organ of newly hatched bobtail squid. At night, the bacteria produce a blue glow that researchers believe obscures a squid's silhouette and helps protect it from predators. The light organ has pockets, or crypts, in the squid's skin that provide nutrients and a safe environment for the bacteria. "When the squid hatches, it doesn't yet have any bacteria in its light organ," said Miyashiro. "But bacteria in the environment quickly colonize the squid's light organ." Some of these different bacteria strains can coexist, but others can't. "Microbial symbioses are essentially universal in animals, and are crucial to the health and development of both partners," says Irwin Forseth, a program director in the National Science Foundation's Division of Integrative Organismal Systems, which funded the research. "The results from this study highlight the role small genetic changes can play in microbe interactions. Increased understanding will allow us to better predict organisms' performance in changing environments."

Image credit: Andrew Cecere

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A new study shows that graphene sheets can block the signals mosquitoes use to identify a blood meal, potentially enabling a new chemical-free approach to mosquito bite prevention. Researchers showed that multilayer graphene can provide a twofold defense against mosquito bites. The ultra-thin yet strong material acts as a barrier that mosquitoes are unable to bite through. At the same time, experiments showed that graphene also blocks chemical signals mosquitoes use to sense that a blood meal is near, blunting their urge to bite in the first place. The findings suggest that clothing with a graphene lining could be an effective mosquito barrier.

Image credit: Hurt Lab/Brown University

Source: Clive Maund for Streetwise Reports   05/04/2020

Notwithstanding the Fed's seemingly limitless ability to create money to throw at the stock market, which has caused it to rally in recent weeks in the face of a dead economy and apocalyptic jobs data and earnings, etc., all the charts we are going to look at here point to another severe downleg soon.

My attention was drawn to a bearish Rising Wedge completing in the London FTSE index by a colleague in England. So I took a look at it, and sure enough it is. So, I thought I'd take a look at a couple of other European indices, the CAC 40 in France and the German DAX Composite, which showed a very similar picture. Their charts are shown below and as you will see, they are both very bearish, and point to a break lower soon leading to a severe decline.

You will recall that we were thrown somewhat a week or two ago, when the main U.S. indices, the Dow Jones Industrials and the S&P500 index, broke down from their bearish Rising Wedges but then didn't follow through, and instead rose to new highs for the rally from the March lows, which caused us to dump our Puts and then bide our time to see what transpired. The sharp drop at the end of the month—this past Friday—jolted me into action and prompted me to hunt around in a quest for greater clarity regarding what is going on, and it has turned out to be a rewarding search.

While it's not exactly clear what is going on with the main U.S. indices, the picture becomes much clearer when we look at the broader but much less used Wilshire 5000 index. Take a look at this first of all—it's a 5-month chart for the Wilshire 5000 that reveals that it didn't break down from its Rising Wedge about 10 days ago, unlike the Dow Industrials and the S&P500 index, but it did last Friday, which happened to be the end of the month, by a significant margin. This is regarded as an ominous development that probably marks the start of the second major downleg of this bear market. We can also see that the countertrend rally got stopped by the important resistance level shown.

Now take a look at this. The following chart shows that the breakdown from the Wedge happened just two days after the Wilshire 5000 had arrived at an upper range Fibonacci target at a retracement level of 61.8% of the preceding first leg down of the bear market. This is normally as far as a retracement following the first leg down of a bear market gets, and the same happened following the Tech bubble peak in 2000 and the start of the 2007–2008 meltdown.

If we now compare the Wilshire charts above with the S&P500 index chart we realize that the breakdown by the latter about 10 days ago was a false breakdown, inasmuch as, as we have just seen, the Wilshire did not break down at that time.

If we see another heavy drop in the broad stock market shortly, it is of course reasonable to presume that it will coincide with a strong rally in the dollar, so how does that look now? On the following 5-month chart for the dollar index, which has the S&P500 index placed above and gold below for direct comparison, there are several very important points to observe. The first is that when the market tanked into mid-March, the dollar soared just as we would expect it to and as happened in 2008. Then it dropped back sharply later in March as the market rebounded, but it has since been tracking sideways in a trading range marking time as the stock market continued to ascend to complete its relief rally. Right now it is at the support at the bottom of this range where a doji candle formed on Friday suggesting that it is about to start higher again. If the market now proceeds to tank in a second major downwave then we can expect the dollar to soar again, bust out of the top of the current range and probably exceed its mid-March highs.

If the dollar soars then commodities are likely to take another broadside, just as in the first half of March, and just as in 2008, and gold and silver are unlikely to be spared—the Gold Miners Bullish Percent Index is now at an extreme reading of 92% bullish. Copper in particular looks like it will get crushed by another downwave that should take it to new bear market lows by a wide margin.

Originally posted on CliveMaund.com at 4.35 pm EDT on 2nd May 2020.

Clive Maund has been president of www.clivemaund.com, a successful resource sector website, since its inception in 2003. He has 30 years' experience in technical analysis and has worked for banks, commodity brokers and stockbrokers in the City of London. He holds a Diploma in Technical Analysis from the UK Society of Technical Analysts.

Disclosure:
1) Statements and opinions expressed are the opinions of Clive Maund and not of Streetwise Reports or its officers. Clive Maund is wholly responsible for the validity of the statements. Streetwise Reports was not involved in any aspect of the article preparation. Clive Maund was not paid by Streetwise Reports LLC for this article. Streetwise Reports was not paid by the author to publish or syndicate this article.
2) This article does not constitute investment advice. Each reader is encouraged to consult with his or her individual financial professional and any action a reader takes as a result of information presented here is his or her own responsibility. By opening this page, each reader accepts and agrees to Streetwise Reports' terms of use and full legal disclaimer. This article is not a solicitation for investment. Streetwise Reports does not render general or specific investment advice and the information on Streetwise Reports should not be considered a recommendation to buy or sell any security. Streetwise Reports does not endorse or recommend the business, products, services or securities of any company mentioned on Streetwise Reports.
3) From time to time, Streetwise Reports LLC and its directors, officers, employees or members of their families, as well as persons interviewed for articles and interviews on the site, may have a long or short position in securities mentioned. Directors, officers, employees or members of their immediate families are prohibited from making purchases and/or sales of those securities in the open market or otherwise from the time of the interview or the decision to write an article until three business days after the publication of the interview or article. The foregoing prohibition does not apply to articles that in substance only restate previously published company releases.

Charts provided by the author.

CliveMaund.com Disclosure:
The above represents the opinion and analysis of Mr Maund, based on data available to him, at the time of writing. Mr. Maund's opinions are his own, and are not a recommendation or an offer to buy or sell securities. Mr. Maund is an independent analyst who receives no compensation of any kind from any groups, individuals or corporations mentioned in his reports. As trading and investing in any financial markets may involve serious risk of loss, Mr. Maund recommends that you consult with a qualified investment advisor, one licensed by appropriate regulatory agencies in your legal jurisdiction and do your own due diligence and research when making any kind of a transaction with financial ramifications. Although a qualified and experienced stock market analyst, Clive Maund is not a Registered Securities Advisor. Therefore Mr. Maund's opinions on the market and stocks can only be construed as a solicitation to buy and sell securities when they are subject to the prior approval and endorsement of a Registered Securities Advisor operating in accordance with the appropriate regulations in your area of jurisdiction.

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