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90-780: [REDACTED] Look up vesper in Wiktionary, the free dictionary. Vesper means evening in Classical Latin . It may also refer to: Places [ edit ] Vesper, Kansas , an unincorporated community in the United States Vesper, Oregon , an unincorporated community in the United States Vesper, Wisconsin , a village in the United States Vesper, an abandoned village southwest of Swift Current, Saskatchewan , Canada Vesper Peak ,

180-518: A Bakerian Lecture in 1940 by Nevil Sidgwick and Herbert Powell of the University of Oxford . In 1957, Ronald Gillespie and Ronald Sydney Nyholm of University College London refined this concept into a more detailed theory, capable of choosing between various alternative geometries. VSEPR theory is used to predict the arrangement of electron pairs around central atoms in molecules, especially simple and symmetric molecules. A central atom

270-846: A sigma bond with an adjacent atom lies further from the central atom than a nonbonding (lone) pair of that atom, which is held close to its positively charged nucleus. VSEPR theory therefore views repulsion by the lone pair to be greater than the repulsion by a bonding pair. As such, when a molecule has 2 interactions with different degrees of repulsion, VSEPR theory predicts the structure where lone pairs occupy positions that allow them to experience less repulsion. Lone pair–lone pair (lp–lp) repulsions are considered stronger than lone pair–bonding pair (lp–bp) repulsions, which in turn are considered stronger than bonding pair–bonding pair (bp–bp) repulsions, distinctions that then guide decisions about overall geometry when 2 or more non-equivalent positions are possible. For instance, when 5 valence electron pairs surround

360-434: A tetrahedron , and the bond angle is cos (− 1 ⁄ 3 ) ≈ 109° 28′. This is referred to as an AX 4 type of molecule. As mentioned above, A represents the central atom and X represents an outer atom. The ammonia molecule (NH 3 ) has three pairs of electrons involved in bonding, but there is a lone pair of electrons on the nitrogen atom. It is not bonded with another atom; however, it influences

450-471: A T-shaped geometry, instead of a trigonal planar geometry like its lighter congener BF 3 . In contrast, the extra stability of the 7p 1/2 electrons in tennessine are predicted to make TsF 3 trigonal planar, unlike the T-shaped geometry observed for IF 3 and predicted for At F 3 ; similarly, Og F 4 should have a tetrahedral geometry, while XeF 4 has a square planar geometry and Rn F 4

540-424: A central atom, they adopt a trigonal bipyramidal molecular geometry with two collinear axial positions and three equatorial positions. An electron pair in an axial position has three close equatorial neighbors only 90° away and a fourth much farther at 180°, while an equatorial electron pair has only two adjacent pairs at 90° and two at 120°. The repulsion from the close neighbors at 90° is more important, so that

630-478: A certain sense, therefore, Latin was studied as a dead language, while it was still a living." Also problematic in Teuffel's scheme is its appropriateness to the concept of classical Latin. Cruttwell addresses the issue by altering the concept of the classical. The "best" Latin is defined as "golden" Latin, the second of the three periods. The other two periods (considered "classical") are left hanging. By assigning

720-688: A character from a book series by Lloyd Alexander Vesper Lynd , a character in the James Bond novel and film Casino Royale Vesper, a village in the Ultima series of video games Organizations [ edit ] Vesper Boat Club , an amateur rowing club in Philadelphia, Pennsylvania, United States Vesper Country Club , one of the first golf courses in the United States Science [ edit ] Vesper bat ,

810-432: A d configuration as for the tetrachloroplatinate ( PtCl 4 ) ion. The explanation of the shape of square planar complexes involves electronic effects and requires the use of crystal field theory . Some transition metal complexes with low d electron count have unusual geometries, which can be ascribed to d subshell bonding interaction. Gillespie found that this interaction produces bonding pairs that also occupy

900-433: A detailed analysis of style, whereas Teuffel was more concerned with history. Like Teuffel, Cruttwell encountered issues while attempting to condense the voluminous details of time periods in an effort to capture the meaning of phases found in their various writing styles. Like Teuffel, he has trouble finding a name for the first of the three periods (the current Old Latin phase), calling it "from Livius to Sulla ." He says

990-471: A form of Greek that was considered model. Before then, the term classis , in addition to being a naval fleet, was a social class in one of the diachronic divisions of Roman society in accordance with property ownership under the Roman constitution. The word is a transliteration of Greek κλῆσις (clēsis, or "calling") used to rank army draftees by property from first to fifth class. Classicus refers to those in

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1080-672: A mountain in Washington State, United States People [ edit ] Heike Vesper (born 1970), German marine biologist Iulian Vesper (1908–1986), Romanian writer Rose Vesper , member of the Ohio House of Representatives (1993–2000) Rudolf Vesper (born 1939), East German Olympic gold medalist in Greco-Roman wrestling Will Vesper (1882–1962), German author and literary critic Arts, entertainment, and media [ edit ] Vesper (novel) ,

1170-407: A phase of styles. The ancient authors themselves first defined style by recognizing different kinds of sermo , or "speech". By valuing Classical Latin as "first class", it was better to write with Latinitas selected by authors who were attuned to literary and upper-class languages of the city as a standardized style. All sermo that differed from it was a different style. Thus, in rhetoric, Cicero

1260-408: A single non-bonding electron than on a pair of non-bonding electrons. In effect, they considered nitrogen dioxide as an AX 2 E 0.5 molecule, with a geometry intermediate between NO 2 and NO 2 . Similarly, chlorine dioxide (ClO 2 ) is an AX 2 E 1.5 molecule, with a geometry intermediate between ClO 2 and ClO 2 . Finally, the methyl radical (CH 3 )

1350-534: A slight alteration in approach, making it clear that his terms applied to Latin and not just to the period. He also changed his dating scheme from AUC to modern BC/AD. Though he introduces das silberne Zeitalter der römischen Literatur , (The Silver Age of Roman Literature) from the death of Augustus to the death of Trajan (14–117 AD), he also mentions parts of a work by Seneca the Elder , a wenig Einfluss der silbernen Latinität (a slight influence of silver Latin). It

1440-448: A unit. There are groups of compounds where VSEPR fails to predict the correct geometry. The shapes of heavier Group 14 element alkyne analogues (RM≡MR, where M = Si, Ge, Sn or Pb) have been computed to be bent. One example of the AX 2 E 2 geometry is molecular lithium oxide , Li 2 O, a linear rather than bent structure, which is ascribed to its bonds being essentially ionic and

1530-420: A young-adult novel by Jeff Sampson Vesper (film) , a 2022 Lithuanian-French-Belgian science-fiction film directed by Kristina Buožytė and Bruno Samper Vesper, an organization in the manga and anime series Mahoromatic Vesper, a banshee with unusually magical singing abilities from animated television series Mysticons Vesper Family, a family in the book series The 39 Clues Vesper Holly ,

1620-729: Is Cruttwell's Augustan Epoch (42 BC – 14 AD). The literary histories list includes all authors from Canonical to the Ciceronian Age—even those whose works are fragmented or missing altogether. With the exception of a few major writers, such as Cicero, Caesar, Virgil and Catullus, ancient accounts of Republican literature praise jurists and orators whose writings, and analyses of various styles of language cannot be verified because there are no surviving records. The reputations of Aquilius Gallus, Quintus Hortensius Hortalus , Lucius Licinius Lucullus , and many others who gained notoriety without readable works, are presumed by their association within

1710-671: Is a rare example of a compound with a steric number of 9, which has a tricapped trigonal prismatic geometry. Steric numbers beyond 9 are very rare, and it is not clear what geometry is generally favoured. Possible geometries for steric numbers of 10, 11, 12, or 14 are bicapped square antiprismatic (or bicapped dodecadeltahedral ), octadecahedral , icosahedral , and bicapped hexagonal antiprismatic , respectively. No compounds with steric numbers this high involving monodentate ligands exist, and those involving multidentate ligands can often be analysed more simply as complexes with lower steric numbers when some multidentate ligands are treated as

1800-443: Is a square antiprism with minimal distortion, despite having a lone pair. One rationalization is that steric crowding of the ligands allows little or no room for the non-bonding lone pair; another rationalization is the inert-pair effect . The Kepert model predicts that ML 4 transition metal molecules are tetrahedral in shape, and it cannot explain the formation of square planar complexes. The majority of such complexes exhibit

1890-400: Is also caused by bonding interaction of the ligands with the d subshell of the metal atom, thus influencing the molecular geometry. Relativistic effects on the electron orbitals of superheavy elements is predicted to influence the molecular geometry of some compounds. For instance, the 6d 5/2 electrons in nihonium play an unexpectedly strong role in bonding, so NhF 3 should assume

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1980-443: Is clear that his mindset had shifted from Golden and Silver Ages to Golden and Silver Latin, also to include Latinitas , which at this point must be interpreted as Classical Latin. He may have been influenced in that regard by one of his sources E. Opitz, who in 1852 had published specimen lexilogiae argenteae latinitatis , which includes Silver Latinity. Though Teuffel's First Period was equivalent to Old Latin and his Second Period

2070-405: Is defined in this theory as an atom which is bonded to two or more other atoms, while a terminal atom is bonded to only one other atom. For example in the molecule methyl isocyanate (H 3 C-N=C=O), the two carbons and one nitrogen are central atoms, and the three hydrogens and one oxygen are terminal atoms. The geometry of the central atoms and their non-bonding electron pairs in turn determine

2160-488: Is different from Wikidata All article disambiguation pages All disambiguation pages Classical Latin Classical Latin is the form of Literary Latin recognized as a literary standard by writers of the late Roman Republic and early Roman Empire . It formed parallel to Vulgar Latin around 75 BC out of Old Latin , and developed by the 3rd century AD into Late Latin . In some later periods,

2250-426: Is greater than or equal to that of the central atom. In O(SiH 3 ) 2 , the central atom is more electronegative, and the lone pairs are less localized and more weakly repulsive. The larger Si–O–Si bond angle results from this and strong ligand-ligand repulsion by the relatively large -SiH 3 ligand. Burford et al showed through X-ray diffraction studies that Cl 3 Al–O–PCl 3 has a linear Al–O–P bond angle and

2340-607: Is known as "classical" Latin literature . The term refers to the canonical relevance of literary works written in Latin in the late Roman Republic , and early to middle Roman Empire . "[T]hat is to say, that of belonging to an exclusive group of authors (or works) that were considered to be emblematic of a certain genre." The term classicus (masculine plural classici ) was devised by the Romans to translate Greek ἐγκριθέντες (encrithentes), and "select" which refers to authors who wrote in

2430-473: Is not that of the golden age... Evidently, Teuffel received ideas about golden and silver Latin from an existing tradition and embedded them in a new system, transforming them as he thought best. In Cruttwell's introduction, the Golden Age is dated 80 BC – AD 14 (from Cicero to Ovid ), which corresponds to Teuffel's findings. Of the "Second Period", Cruttwell paraphrases Teuffel by saying it "represents

2520-413: Is predicted to have the same. The VSEPR theory can be extended to molecules with an odd number of electrons by treating the unpaired electron as a "half electron pair"—for example, Gillespie and Nyholm suggested that the decrease in the bond angle in the series NO 2 (180°), NO 2 (134°), NO 2 (115°) indicates that a given set of bonding electron pairs exert a weaker repulsion on

2610-601: Is that period in which the climax was reached in the perfection of form, and in most respects also in the methodical treatment of the subject-matters. It may be subdivided between the generations, in the first of which (the Ciceronian Age) prose culminated, while poetry was principally developed in the Augustan Age. The Ciceronian Age was dated 671–711 AUC (83–43 BC), ending just after the death of Marcus Tullius Cicero. The Augustan 711–67 AUC (43 BC – 14 AD) ends with

2700-587: Is the first known reference (possibly innovated during this time) to Classical Latin applied by authors, evidenced in the authentic language of their works. Imitating Greek grammarians, Romans such as Quintilian drew up lists termed indices or ordines modeled after the ones created by the Greeks, which were called pinakes . The Greek lists were considered classical, or recepti scriptores ("select writers"). Aulus Gellius includes authors like Plautus , who are considered writers of Old Latin and not strictly in

2790-499: Is therefore a non-VSEPR molecule. Some AX 6 E 1 molecules, e.g. xenon hexafluoride (XeF 6 ) and the Te(IV) and Bi(III) anions, TeCl 6 , TeBr 6 , BiCl 6 , BiBr 6 and BiI 6 , are octahedral, rather than pentagonal pyramids, and the lone pair does not affect the geometry to the degree predicted by VSEPR. Similarly, the octafluoroxenate ion ( XeF 8 ) in nitrosonium octafluoroxenate(VI)

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2880-450: Is to be distinguished by: until 75 BC Old Latin 75 BC – 200 AD Classical Latin 200–700 Late Latin 700–1500 Medieval Latin 1300–1500 Renaissance Latin 1300– present Neo-Latin 1900– present Contemporary Latin VSEPR theory The premise of VSEPR is that the valence electron pairs surrounding an atom tend to repel each other. The greater

2970-619: The Antonines ), and the 3rd through 6th centuries. Of the Silver Age proper, Teuffel points out that anything like freedom of speech had vanished with Tiberius : ...the continual apprehension in which men lived caused a restless versatility... Simple or natural composition was considered insipid; the aim of language was to be brilliant... Hence it was dressed up with abundant tinsel of epigrams, rhetorical figures and poetical terms... Mannerism supplanted style, and bombastic pathos took

3060-483: The classici scriptores declined in the medieval period as the best form of the language yielded to medieval Latin , inferior to classical standards. The Renaissance saw a revival in Roman culture, and with it, the return of Classic ("the best") Latin. Thomas Sébillet 's Art Poétique (1548), "les bons et classiques poètes françois", refers to Jean de Meun and Alain Chartier , who the first modern application of

3150-474: The electron density of molecules. Such quantum chemical topology (QCT) methods include the electron localization function (ELF) and the quantum theory of atoms in molecules (AIM or QTAIM). The idea of a correlation between molecular geometry and number of valence electron pairs (both shared and unshared pairs) was originally proposed in 1939 by Ryutaro Tsuchida in Japan, and was independently presented in

3240-466: The prima classis ("first class"), such as the authors of polished works of Latinitas , or sermo urbanus . It contains nuances of the certified and the authentic, or testis classicus ("reliable witness"). It was under this construct that Marcus Cornelius Fronto (an African - Roman lawyer and language teacher) used scriptores classici ("first-class" or "reliable authors") in the second century AD. Their works were viewed as models of good Latin. This

3330-664: The Classical Latin period formed the model for the language taught and used in later periods across Europe and beyond. While the Latin used in different periods deviated from "Classical" Latin, efforts were periodically made to relearn and reapply the models of the Classical period, for instance by Alcuin during the reign of Charlemagne , and later during the Renaissance , producing the highly classicising form of Latin now known as Neo-Latin . "Good Latin" in philology

3420-463: The English translation of A History of Roman Literature gained immediate success. In 1877, Charles Thomas Cruttwell produced a similar work in English. In his preface, Cruttwell notes "Teuffel's admirable history, without which many chapters in the present work could not have attained completeness." He also credits Wagner. Cruttwell adopts the time periods found in Teuffel's work, but he presents

3510-421: The Golden Age. A list of canonical authors of the period whose works survived in whole or in part is shown here: The Golden Age is divided by the assassination of Julius Caesar . In the wars that followed, a generation of Republican literary figures was lost. Cicero and his contemporaries were replaced by a new generation who spent their formative years under the old constructs, and forced to make their mark under

3600-533: The Greek name given to the planet Venus at sunset Hesperus , the personification of the evening star Vesper in Greek mythology HMS  Vesper  (D55) , a British destroyer in commission in the Royal Navy from 1918 to the 1920s and from 1939 to 1945 See also [ edit ] Vespa Vespers (disambiguation) VSEPR theory in chemistry, often pronounced "Vesper" Topics referred to by

3690-451: The H 3 C−C=C angle (124°) is larger than the H 3 C−C−CH 3 angle (111.5°). However, in the carbonate ion, CO 3 , all three C−O bonds are equivalent with angles of 120° due to resonance . The "AXE method" of electron counting is commonly used when applying the VSEPR theory. The electron pairs around a central atom are represented by a formula AX m E n , where A represents

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3780-602: The Imperial Period, and is divided into die Zeit der julischen Dynastie ( 14–68); die Zeit der flavischen Dynastie (69–96), and die Zeit des Nerva und Trajan (96–117). Subsequently, Teuffel goes over to a century scheme: 2nd, 3rd, etc., through 6th. His later editions (which came about towards the end of the 19th century) divide the Imperial Age into parts: 1st century (Silver Age), 2nd century (the Hadrian and

3870-492: The Roman Empire . Once again, Cruttwell evidences some unease with his stock pronouncements: "The Natural History of Pliny shows how much remained to be done in fields of great interest." The idea of Pliny as a model is not consistent with any sort of decline. Moreover, Pliny did his best work under emperors who were as tolerant as Augustus had been. To include some of the best writings of the Silver Age, Cruttwell extended

3960-474: The Second Period in his major work, das goldene Zeitalter der römischen Literatur ( Golden Age of Roman Literature ), dated 671–767 AUC (83 BC – AD 14), according to his own recollection. The timeframe is marked by the dictatorship of Lucius Cornelius Sulla Felix and the death of the emperor Augustus . Wagner's translation of Teuffel's writing is as follows: The golden age of the Roman literature

4050-421: The adoption of roughly the same geometries when they are tied together at their stems as the corresponding number of electron pairs. For example, five balloons tied together adopt the trigonal bipyramidal geometry, just as do the five bonding pairs of a PCl 5 molecule. The steric number of a central atom in a molecule is the number of atoms bonded to that central atom, called its coordination number , plus

4140-430: The advance would be perceptible by us." In time, some of Cruttwell's ideas become established in Latin philology. While praising the application of rules to classical Latin (most intensely in the Golden Age, he says "In gaining accuracy, however, classical Latin suffered a grievous loss. It became cultivated as distinct from a natural language... Spontaneity, therefore, became impossible and soon invention also ceased... In

4230-399: The ancient definition, and some of the very best writing of any period in world history was deemed stilted, degenerate, unnatural language. The Silver Age furnishes the only two extant Latin novels: Apuleius's The Golden Ass and Petronius's Satyricon . Writers of the Silver Age include: Of the additional century granted by Cruttwell to Silver Latin, Teuffel says: "The second century

4320-466: The apices of a tetrahedron. However, the bond angle between the two O–H bonds is only 104.5°, rather than the 109.5° of a regular tetrahedron, because the two lone pairs (whose density or probability envelopes lie closer to the oxygen nucleus) exert a greater mutual repulsion than the two bond pairs. A bond of higher bond order also exerts greater repulsion since the pi bond electrons contribute. For example in isobutylene , (H 3 C) 2 C=CH 2 ,

4410-430: The atom. Therefore, the predicted geometry is trigonal . Likewise, for 4 electron pairs, the optimal arrangement is tetrahedral . As a tool in predicting the geometry adopted with a given number of electron pairs, an often used physical demonstration of the principle of minimal electron pair repulsion utilizes inflated balloons. Through handling, balloons acquire a slight surface electrostatic charge that results in

4500-558: The atomic nuclei only, which is trigonal-pyramidal for NH 3 . Steric numbers of 7 or greater are possible, but are less common. The steric number of 7 occurs in iodine heptafluoride (IF 7 ); the base geometry for a steric number of 7 is pentagonal bipyramidal. The most common geometry for a steric number of 8 is a square antiprismatic geometry. Examples of this include the octacyanomolybdate ( Mo(CN) 8 ) and octafluorozirconate ( ZrF 8 ) anions. The nonahydridorhenate ion ( ReH 9 ) in potassium nonahydridorhenate

4590-527: The axial positions experience more repulsion than the equatorial positions; hence, when there are lone pairs, they tend to occupy equatorial positions as shown in the diagrams of the next section for steric number five. The difference between lone pairs and bonding pairs may also be used to rationalize deviations from idealized geometries. For example, the H 2 O molecule has four electron pairs in its valence shell: two lone pairs and two bond pairs. The four electron pairs are spread so as to point roughly towards

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4680-489: The bond angles may be slightly different from the ones where all the outside atoms are the same. For example, the double-bond carbons in alkenes like C 2 H 4 are AX 3 E 0 , but the bond angles are not all exactly 120°. Likewise, SOCl 2 is AX 3 E 1 , but because the X substituents are not identical, the X–A–X angles are not all equal. Based on the steric number and distribution of X s and E s, VSEPR theory makes

4770-425: The central atom and always has an implied subscript one. Each X represents a ligand (an atom bonded to A). Each E represents a lone pair of electrons on the central atom. The total number of X and E is known as the steric number. For example in a molecule AX 3 E 2 , the atom A has a steric number of 5. When the substituent (X) atoms are not all the same, the geometry is still approximately valid, but

4860-402: The common vernacular , however, as Vulgar Latin ( sermo vulgaris and sermo vulgi ), in contrast to the higher register that they called latinitas , sometimes translated as "Latinity". Latinitas was also called sermo familiaris ("speech of the good families"), sermo urbanus ("speech of the city"), and in rare cases sermo nobilis ("noble speech"). Besides the noun Latinitas , it

4950-474: The death of Augustus. The Ciceronian Age is further divided by the consulship of Cicero in 691 AUC (63 BC) into a first and second half. Authors are assigned to these periods by years of principal achievements. The Golden Age had already made an appearance in German philology, but in a less systematic way. In a translation of Bielfeld's Elements of universal erudition (1770): The Second Age of Latin began about

5040-443: The extinction of freedom... Hence arose a declamatory tone, which strove by frigid and almost hysterical exaggeration to make up for the healthy stimulus afforded by daily contact with affairs. The vein of artificial rhetoric, antithesis and epigram... owes its origin to this forced contentment with an uncongenial sphere. With the decay of freedom, taste sank... In Cruttwell's view (which had not been expressed by Teuffel), Silver Latin

5130-445: The former was regarded as good or proper Latin; the latter as debased, degenerate, or corrupted. The word Latin is now understood by default to mean "Classical Latin"; for example, modern Latin textbooks almost exclusively teach Classical Latin. Cicero and his contemporaries of the late republic referred to the Latin language, in contrast to other languages such as Greek, as lingua latina or sermo latinus . They distinguished

5220-422: The fundamental characteristics of a language. The latter provides unity, allowing it to be referred to by a single name. Thus Old Latin, Classical Latin, Vulgar Latin , etc., are not considered different languages, but are all referred to by the term, Latin . This is an ancient practice continued by moderns rather than a philological innovation of recent times. That Latin had case endings is a fundamental feature of

5310-410: The geometry around all such atoms corresponds to the VSEPR geometry for AX n with 0 lone pairs E. This is often written ML n , where M = metal and L = ligand. The Kepert model predicts the following geometries for coordination numbers of 2 through 9: The methane molecule (CH 4 ) is tetrahedral because there are four pairs of electrons. The four hydrogen atoms are positioned at the vertices of

5400-456: The geometry of the larger whole molecule. The number of electron pairs in the valence shell of a central atom is determined after drawing the Lewis structure of the molecule, and expanding it to show all bonding groups and lone pairs of electrons. In VSEPR theory, a double bond or triple bond is treated as a single bonding group. The sum of the number of atoms bonded to a central atom and

5490-579: The highest excellence in prose and poetry." The Ciceronian Age (known today as the "Republican Period") is dated 80–42 BC, marked by the Battle of Philippi . Cruttwell omits the first half of Teuffel's Ciceronian, and starts the Golden Age at Cicero's consulship in 63 BC—an error perpetuated in Cruttwell's second edition. He likely meant 80 BC, as he includes Varro in Golden Latin. Teuffel's Augustan Age

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5580-457: The language "is marked by immaturity of art and language, by a vigorous but ill-disciplined imitation of Greek poetical models, and in prose by a dry sententiousness of style, gradually giving way to a clear and fluent strength..." These abstracts have little meaning to those not well-versed in Latin literature. In fact, Cruttwell admits "The ancients, indeed, saw a difference between Ennius , Pacuvius , and Accius , but it may be questioned whether

5670-511: The language. Whether a given form of speech prefers to use prepositions such as ad , ex , de, for "to", "from" and "of" rather than simple case endings is a matter of style. Latin has a large number of styles. Each and every author has a style, which typically allows his prose or poetry to be identified by experienced Latinists. Problems in comparative literature have risen out of group styles finding similarity by period, in which case one may speak of Old Latin, Silver Latin, Late Latin as styles or

5760-512: The largest, best-known family of bats Vesper mouse , a rodent genus Vesper sparrow , a medium-sized bird Vesper (plant) , a genus of plants in the family Apiaceae Vesper mission, a planned Venus chemistry and dynamics orbiter of the NASA Discovery Program Other uses [ edit ] Vesper (cocktail) , an alcoholic beverage recipe popularized by Ian Fleming The Roman equivalent of Hesperus ,

5850-498: The lone pair helps to determine the geometry. The lone pairs on transition metal atoms are usually stereochemically inactive, meaning that their presence does not change the molecular geometry. For example, the hexaaquo complexes M(H 2 O) 6 are all octahedral for M = V , Mn , Co , Ni and Zn , despite the fact that the electronic configurations of the central metal ion are d , d , d , d and d respectively. The Kepert model ignores all lone pairs on transition metal atoms, so that

5940-430: The number of lone pairs formed by its nonbonding valence electrons is known as the central atom's steric number. The electron pairs (or groups if multiple bonds are present) are assumed to lie on the surface of a sphere centered on the central atom and tend to occupy positions that minimize their mutual repulsions by maximizing the distance between them. The number of electron pairs (or groups), therefore, determines

6030-464: The number of lone pairs of valence electrons on the central atom. In the molecule SF 4 , for example, the central sulfur atom has four ligands ; the coordination number of sulfur is four. In addition to the four ligands, sulfur also has one lone pair in this molecule. Thus, the steric number is 4 + 1 = 5. The overall geometry is further refined by distinguishing between bonding and nonbonding electron pairs. The bonding electron pair shared in

6120-448: The other, would savour of artificial restriction rather than that of a natural classification." The contradiction remains—Terence is, and is not a classical author, depending on the context. Teuffel's definition of the "First Period" of Latin was based on inscriptions, fragments, and the literary works of the earliest known authors. Though he does use the term "Old Roman" at one point, most of these findings remain unnamed. Teuffel presents

6210-431: The overall geometry that they will adopt. For example, when there are two electron pairs surrounding the central atom, their mutual repulsion is minimal when they lie at opposite poles of the sphere. Therefore, the central atom is predicted to adopt a linear geometry. If there are 3 electron pairs surrounding the central atom, their repulsion is minimized by placing them at the vertices of an equilateral triangle centered on

6300-424: The overall shape through repulsions. As in methane above, there are four regions of electron density. Therefore, the overall orientation of the regions of electron density is tetrahedral. On the other hand, there are only three outer atoms. This is referred to as an AX 3 E type molecule because the lone pair is represented by an E. By definition, the molecular shape or geometry describes the geometric arrangement of

6390-510: The period of classical Latin. The classical Romans distinguished Old Latin as prisca Latinitas and not sermo vulgaris . Each author's work in the Roman lists was considered equivalent to one in the Greek. In example, Ennius was the Latin Homer , Aeneid was the equivalent of Iliad , etc. The lists of classical authors were as far as the Roman grammarians went in developing a philology . The topic remained at that point while interest in

6480-410: The period through the death of Marcus Aurelius (180 AD). The philosophic prose of a good emperor was in no way compatible with either Teuffel's view of unnatural language, or Cruttwell's depiction of a decline. Having created these constructs, the two philologists found they could not entirely justify them. Apparently, in the worst implication of their views, there was no such thing as Classical Latin by

6570-583: The philological notion of classical Latin through a typology similar to the Ages of Man , setting out the Golden and Silver Ages of classical Latin. Wilhem Wagner, who published Teuffel's work in German, also produced an English translation which he published in 1873. Teuffel's classification, still in use today (with modifications), groups classical Latin authors into periods defined by political events rather than by style. Teuffel went on to publish other editions, but

6660-419: The place of quiet power. The content of new literary works was continually proscribed by the emperor, who exiled or executed existing authors and played the role of literary man, himself (typically badly). Artists therefore went into a repertory of new and dazzling mannerisms, which Teuffel calls "utter unreality." Cruttwell picks up this theme: The foremost of these [characteristics] is unreality, arising from

6750-405: The predictions in the following tables. For main-group elements , there are stereochemically active lone pairs E whose number can vary between 0 to 3. Note that the geometries are named according to the atomic positions only and not the electron arrangement. For example, the description of AX 2 E 1 as a bent molecule means that the three atoms AX 2 are not in one straight line, although

6840-572: The repulsion, the higher in energy (less stable) the molecule is. Therefore, the VSEPR-predicted molecular geometry of a molecule is the one that has as little of this repulsion as possible. Gillespie has emphasized that the electron-electron repulsion due to the Pauli exclusion principle is more important in determining molecular geometry than the electrostatic repulsion . The insights of VSEPR theory are derived from topological analysis of

6930-647: The respective antipodal points (ligand opposed) of the sphere. This phenomenon is an electronic effect resulting from the bilobed shape of the underlying sd hybrid orbitals . The repulsion of these bonding pairs leads to a different set of shapes. The gas phase structures of the triatomic halides of the heavier members of group 2 , (i.e., calcium, strontium and barium halides, MX 2 ), are not linear as predicted but are bent, (approximate X–M–X angles: CaF 2 , 145°; SrF 2 , 120°; BaF 2 , 108°; SrCl 2 , 130°; BaCl 2 , 115°; BaBr 2 , 115°; BaI 2 , 105°). It has been proposed by Gillespie that this

7020-415: The rules of politus (polished) texts may give the appearance of an artificial language. However, Latinitas was a form of sermo (spoken language), and as such, retains spontaneity. No texts by Classical Latin authors are noted for the type of rigidity evidenced by stylized art, with the exception of repetitious abbreviations and stock phrases found on inscriptions. The standards, authors and manuals from

7110-500: The same term [REDACTED] This disambiguation page lists articles associated with the title Vesper . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Vesper&oldid=1238095270 " Categories : Disambiguation pages Place name disambiguation pages Disambiguation pages with surname-holder lists Hidden categories: Short description

7200-515: The strong lithium-lithium repulsion that results. Another example is O(SiH 3 ) 2 with an Si–O–Si angle of 144.1°, which compares to the angles in Cl 2 O (110.9°), (CH 3 ) 2 O (111.7°), and N(CH 3 ) 3 (110.9°). Gillespie and Robinson rationalize the Si–O–Si bond angle based on the observed ability of a ligand's lone pair to most greatly repel other electron pairs when the ligand electronegativity

7290-437: The term "pre-classical" to Old Latin and implicating it to post-classical (or post-Augustan) and silver Latin, Cruttwell realized that his construct was not accordance with ancient usage and assertions: "[T]he epithet classical is by many restricted to the authors who wrote in it [golden Latin]. It is best, however, not to narrow unnecessarily the sphere of classicity; to exclude Terence on the one hand or Tacitus and Pliny on

7380-421: The time of Caesar [his ages are different from Teuffel's], and ended with Tiberius. This is what is called the Augustan Age, which was perhaps of all others the most brilliant, a period at which it should seem as if the greatest men, and the immortal authors, had met together upon the earth, in order to write the Latin language in its utmost purity and perfection... and of Tacitus, his conceits and sententious style

7470-556: The watchful eye of a new emperor. The demand for great orators had ceased, shifting to an emphasis on poetry. Other than the historian Livy , the most remarkable writers of the period were the poets Virgil , Horace , and Ovid . Although Augustus evidenced some toleration to republican sympathizers, he exiled Ovid, and imperial tolerance ended with the continuance of the Julio-Claudian dynasty . Augustan writers include: In his second volume, Imperial Period , Teuffel initiated

7560-489: The words. According to Merriam Webster's Collegiate Dictionary , the term classical (from classicus) entered modern English in 1599, some 50 years after its re-introduction to the continent. In Governor William Bradford 's Dialogue (1648), he referred to synods of a separatist church as "classical meetings", defined by meetings between "young men" from New England and "ancient men" from Holland and England. In 1715, Laurence Echard 's Classical Geographical Dictionary

7650-442: Was a "rank, weed-grown garden," a "decline." Cruttwell had already decried what he saw as a loss of spontaneity in Golden Latin. Teuffel regarded the Silver Age as a loss of natural language, and therefore of spontaneity, implying that it was last seen in the Golden Age. Instead, Tiberius brought about a "sudden collapse of letters." The idea of a decline had been dominant in English society since Edward Gibbon 's Decline and Fall of

7740-484: Was a happy period for the Roman State, the happiest indeed during the whole Empire... But in the world of letters the lassitude and enervation, which told of Rome's decline, became unmistakeable... its forte is in imitation." Teuffel, however, excepts the jurists; others find other "exceptions", recasting Teuffels's view. Style of language refers to repeatable features of speech that are somewhat less general than

7830-459: Was able to define sublime, intermediate, and low styles within Classical Latin. St. Augustine recommended low style for sermons. Style was to be defined by deviation in speech from a standard. Teuffel termed this standard "Golden Latin". John Edwin Sandys , who was an authority in Latin style for several decades, summarizes the differences between Golden and Silver Latin as follows: Silver Latin

7920-400: Was equal to the Golden Age, his Third Period die römische Kaiserheit encompasses both the Silver Age and the centuries now termed Late Latin , in which the forms seemed to break loose from their foundation and float freely. That is, men of literature were confounded about the meaning of "good Latin." The last iteration of Classical Latin is known as Silver Latin. The Silver Age is the first of

8010-737: Was published. In 1736, Robert Ainsworth 's Thesaurus Linguae Latinae Compendarius turned English words and expressions into "proper and classical Latin." In 1768, David Ruhnken 's Critical History of the Greek Orators recast the molded view of the classical by applying the word "canon" to the pinakes of orators after the Biblical canon , or list of authentic books of the Bible. In doing so, Ruhnken had secular catechism in mind. In 1870, Wilhelm Sigismund Teuffel 's Geschichte der Römischen Literatur ( A History of Roman Literature ) defined

8100-472: Was referred to with the adverb latine ("in (good) Latin", literally "Latinly") or its comparative latinius ("in better Latin", literally "more Latinly"). Latinitas was spoken and written. It was the language taught in schools. Prescriptive rules therefore applied to it, and when special subjects like poetry or rhetoric were taken into consideration, additional rules applied. Since spoken Latinitas has become extinct (in favor of subsequent registers),

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