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Hybridization of s and p orbitals to form effective sp hybrid orbitals requires that they have comparable radial extent. While 2p orbitals are on average less than 10% larger than 2s, in part attributable to the lack of a radial node in 2p orbitals, 3p orbitals which have one radial node, exceed the 3s orbitals by 20-33%.{{cite journal|last1=Kaupp|first1=Martin|title=The role of radial nodes of atomic orbitals for chemical bonding and the periodic table|journal=Journal of Computational Chemistry|volume=28|issue=1|year=2007|pages=320–325|issn=01928651|doi=10.1002/jcc.20522}} The difference in extent of s and p orbitals increases further down a group. The hybridization in of atoms in chemical bonds can be analyzed by considering localized molecular orbitals, for example using natural localized molecular orbitals in a natural bond orbital (NBO) scheme. In methane, CH₄, the calculated p/s ratio is approximately 3 consistent with "ideal" sp³ hybridization, whereas for silane, SiH₄, the p/s ratio is closer to 2. A similar trend is seen for the other 2p elements. Substitution of fluorine for hydrogen further decreases the p/s ratio.{{cite book |last1=Kaupp |first1=Martin |editor1-last=Frenking |editor1-first=Gernod |editor2-first=Sason|editor2-last=Shaik|title=The Chemical Bond|publisher=Wiley-VCH|date=2014 |origyear=1st. Pub. 2014|chapter=Chapter 1: Chemical bonding of main group elements|isbn=978-1-234-56789-7 |lastauthoramp=y}}The 2p elements exhibit near ideal hybridization with orthogonal hybrid orbitals. For heavier p block elements this assumption of orthogonality cannot be justified. These deviations from the ideal hybridization were termed hybridization defects by Kutzelnigg. {{cite journal |title=Orthogonal and non-orthogonal hybrids|authors= Kutzelnigg, W.|doi=10.1016/j.ccr.2010.04.011|url=http://www.sciencedirect.com/science/article/pii/0166128088802732|date=August 1988|volume=169|issue= |pages= 403-419 | Journal of Molecular Structure: THEOCHEM}} {{Subscription or libraries|sentence|via=ScienceDirect}}

TY - JOUR

T1 - Orthogonal and non-orthogonal hybrids

JO - Journal of Molecular Structure: THEOCHEM

VL - 169

IS - 0

SP - 403

EP - 419

PY - 1988/8//

T2 -

AU - Kutzelnigg, W.

SN - 0166-1280

DO - http://dx.doi.org/10.1016/0166-1280(88)80273-2

UR - http://www.sciencedirect.com/science/article/pii/0166128088802732

{{cite journal |title=Orthogonal and non-orthogonal hybrids|authors= Kutzelnigg, W.|doi=10.1016/j.ccr.2010.04.011|url=http://www.sciencedirect.com/science/article/pii/0166128088802732|date=August 1988|volume=169|issue= |pages= 403-419 | Journal of Molecular Structure: THEOCHEM}} {{Subscription or libraries|sentence|via=ScienceDirect}}

Kutzelnigg in 1986 highlighted carbon as a unique case which adheres most closely to the conventional sp hybridization model.

Phosphate glasses have been used in lasers (for example Nd doped glass), alkali metal phosphate glasses are sequestration agents for hard water and dispersants for clay processing as well as pigment manufacture. Biocompatible phosphate glases are used in medical applications. Iron phosphate glasses have been investigated for use as hosts for nuclear waste. The phosphate glasses were first investigated by Schott and coworkers in the early part of last century. 20th century by Schott and coworkers. While the glasses have good optical properties such as high transparency to ultraviolet light they were considered to sensitive to moisture to be generally useful. P2O5 was identified by Zachariesen as one of the prototypical network formers in the 1930's.(Take from Brow, Neel and Salih and Neel Pickup reviews) Glasses formed from multiple network formers have been produced, for example aluminophosphate, silicophosphate as well as molybdophosphate and tungstophosphate glasses formed with molybdenum and tungsten oxide Rao, chapter 12 oxide glasses Elsevier

Phosphate glasses are based on phosphorus pentoxide, P₂O₅ as the "network former". Tetrahedral {PO4} units are lnked together by bridging oxygen units. This linking of tetrahedral units is shared with the silicate glasses, which are based on silica as the network former. A structural difference between silicates and phosphates is that while silicates can share all four corners in phosphates a maximum of three corners can be shared. The conventional way of showing the terminal (non-bridging P-O- is as a P=O double bond. The number of shared corners of the {PO₄} tetrahedra is sometimes designated as Qⁱ where i is the number of corners shared.Bioactive functional materials: a perspective on phosphate-based glasses, Abou Neel, Ensanya A., Pickup, David M., Valappil, Sabeel P., Newport, Robert J., Knowles, Jonathan C., 2009,Journal of Materials Chemistry, 19, 6, pages 690 - 701, 10.1039/B810675D, ISSN=0959-9428, url http://pubs.rsc.org/en/content/articlelanding/2009/jm/b810675d#!divAbstract. Crystalline compounds can be prepared as well as amorphous glasses. Phosphate compounds can be classified by their P/O ratio as follows:

Simple binary glasess derived from from P2O5 and a metal single metal oxide, e.g. Na2O, CaO. Ternary has two defferent metal oxides and quaternary 3. The addition of other oxides allows modificaion of the properties of the glasses.

Melt quenching- could use P2O5 but too volatile and readily hydrolysed- use a phosphate compound e.g. metaphosphate and a metal carbonate rather than oxide- metaphosphate and carbonate decompose releasing H2O and CO2 respectively which is useful as it aids in homogenizing the melt. . ?? Neel Salih

Sol-gel methods - allow for unusual oxides such as TiO2 to be incorporated. Alkoxides and ???? form sol- wait for gel- calcine to dehydrate.

Add ing oxide to P2O5 causes depolymerization.

Van wazer suggested that 2Q2 <-> Q3 +Q1 and 2Q1<-> Q2 + Q0m Neel and Salih

These are called because there have a high P/O ratio - contain small anionic units and properties depend on nature of the cations present.

Anionic chains of Q2 terahedra terminated by Q1 - metaphosphate with a pyro end-- synthon?? perhaps??

First Graham's salt, formed when NaH2PO4 is heated- consists of chains -commercially known as Calgon, an ion exchange water softener. Wiberg The composition of metaphosphate glasses approximates to M2O.P2O5, (M is a group 1 alkali metal e.g. sodium) Neel Salih Consists almst entirely of Q2 units. Effect of replacing alkali metal oxide with alkline earth metal (eg. substitute MgO for Na2O ) is to increase the durability of the glass.

Sensitive to moisture - like P2O5 - some need to nbe kept in sealed ampoules.

Na2O/CaO/P2O5 glasses much studied as biologically compatible.

===

=Ultraphosphates (Article)=

Ultraphosphates are a group of phosphorus oxyanions that contain a higher proportion of phosphorus than metaphosphates.J.P. Attfield, Phosphates, In Encyclopedia of Materials: Science and Technology (Second Edition), edited by K.H. Jürgen Buschow Robert W. CahnMerton C. Flemings Bernhard Ilschner Edward J. Kramer Subhash Mahajan Patrick Veyssière, Elsevier, Oxford, 2001, Pages 6896-6901, {{ISBN|9780080431529}}, http://dx.doi.org/10.1016/B0-08-043152-6/01222-5. (http://www.sciencedirect.com/science/article/pii/B0080431526012225)

Lanthanide ultraphosphates, LnP₅O₁₄ have optical properties that may have industrial applications Marie-Thérèse Averbuch-Pouchot, A. Durif Topics in Phosphate Chemistry World Scientific, 1 Jan 1996, 981-02-2634-9 Ultraphosphates in common with other condensed phosphates (metaphosphates and polyphosphates) are made up of corner sharing {PO₄} units. Where ultraphosphates differ is that they contain {PO₄} units that share three corners. The number of shared corners in the {PO₄} tetrahedra is sometimes designated as Qⁱ where i is the number of corners shared.Bioactive functional materials: a perspective on phosphate-based glasses, Abou Neel, Ensanya A., Pickup, David M., Valappil, Sabeel P., Newport, Robert J., Knowles, Jonathan C., 2009,Journal of Materials Chemistry, 19, 6, pages 690 - 701, 10.1039/B810675D, ISSN=0959-9428, url http://pubs.rsc.org/en/content/articlelanding/2009/jm/b810675d#!divAbstract P₂O₅ contains only Q³ units in all of its forms (molecular P₄O₁₀ and polymeric). Ultraphosphate compounds contain both Q³ and Q² units, whereas metaphosphate compounds contain only Q².

• Brow 2000

:TY - JOUR

:T1 - Review: the structure of simple phosphate glasses

:JO - Journal of Non-Crystalline Solids

:VL - 263–264

:IS - 0

:SP - 1

:EP - 28

:PY - 2000/3/1/

:T2 -

:AU - Brow, Richard K

:SN - 0022-3093

:DO - http://dx.doi.org/10.1016/S0022-3093(99)00620-1

:UR - http://www.sciencedirect.com/science/article/pii/S0022309399006201

• Neel Salih 2011

:TY - CHAP

;AU - Abou Neel, E.A.

:AU - Salih, V.

:AU - Knowles, J.C.

:T1 - 1.117 - Phosphate-Based Glasses

:A2 - Ducheyne, Paul

:BT - Comprehensive Biomaterials

:PB - Elsevier

:CY - Oxford

:PY - 2011///

:SP - 285

:EP - 297

:SN - 978-0-08-055294-1

:DO - http://dx.doi.org/10.1016/B978-0-08-055294-1.00249-X

:UR - http://www.sciencedirect.com/science/article/pii/B978008055294100249X

{{reflist}}

Marie-Thérèse Averbuch-Pouchot, A. Durif Topics in Phosphate Chemistry World Scientific, 1 Jan 1996, 981-02-2634-9

D Corbridge, CHAPTER 3 - Phosphates, Studies in Inorganic Chemistry, Elsevier, 1995, Volume 20, Pages 169-305, ISSN 0169-3158, {{ISBN|9780444893079}}, http://dx.doi.org/10.1016/B978-0-444-89307-9.50008-8.

(http://www.sciencedirect.com/science/article/pii/B9780444893079500088)

J.M. Cole, M.R. Lees, J.A.K. Howard, R.J. Newport, G.A. Saunders, E. Schönherr, Crystal Structures and Magnetic Properties of Rare-Earth Ultraphosphates, RP5O14 (R=La, Nd, Sm, Eu, Gd), Journal of Solid State Chemistry, Volume 150, Issue 2, March 2000, Pages 377-382, ISSN 0022-4596, http://dx.doi.org/10.1006/jssc.1999.8610.

(http://www.sciencedirect.com/science/article/pii/S0022459699986103)

Bioactive functional materials: a perspective on phosphate-based glasses, Abou Neel, Ensanya A., Pickup, David M., Valappil, Sabeel P., Newport, Robert J., Knowles, Jonathan C., 2009,Journal of Materials Chemistry, 19, 6, pages 690 - 701, 10.1039/B810675D, ISSN=0959-9428, url http://pubs.rsc.org/en/content/articlelanding/2009/jm/b810675d#!divAbstract

J.P. Attfield, Phosphates, In Encyclopedia of Materials: Science and Technology (Second Edition), edited by K.H. Jürgen BuschowRobert W. CahnMerton C. FlemingsBernhard IlschnerEdward J. KramerSubhash MahajanPatrick Veyssière, Elsevier, Oxford, 2001, Pages 6896-6901, {{ISBN|9780080431529}}, http://dx.doi.org/10.1016/B0-08-043152-6/01222-5.

(http://www.sciencedirect.com/science/article/pii/B0080431526012225)

Compounds are known that contain anions with the general formulae of (P₂O₅.(PO₃)_n)^n– where n = 2 - 6, P₄O₁₁^2–, P₅O₁₄^3–, P₆O₁₇^4–, P₇O₂₀^5– and P₈O₂₃^6–. The stoichiometry of the anion is no guide to the structure. For example in the lanthaide ultraphosphates, LnP₅O₁₄, the phosphate anionic framework adopts a number of different forms. In Na3Fe₈O₂₃ the anion ₈O₂₃^6– has a cage "molecular" structure.

P5O143–

P6O174-

P7O205–

P8O236-

In the classification of phosphates as salts of acids with the formula mH₂O.nP₂O₅ ultraphosphates have m/n < 1, and richer in P₂O₅ than the metaphosphates ,which are salts of hypothetical acids formulated as H₂O.P₂O₅ with anions P_nO_3n^n–.

An ultraphosphate is a phosphate that is richer in phosphorus pentoxide than the metaphosphates. Examples of some known ultraphosphates showing the proportions of phosphorus pentoxide along with metaphosphate as a comaparison.

Some known ultraphosphates include

{{cite book |last=Corbridge |first=D. |title=Studies in inorganic Chemistry vol. 20|publisher=Elsevier Science B.V. |date=1995 |pages=169-305 |chapter=Chapter 3: Phosphates |isbn=0-444-89307-5|url=http://www.sciencedirect.com/science/article/pii/B9780444893079500088|access-date=January 30, 2015}}{{Subscription or libraries|sentence|via=ScienceDirect}}

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{{cite journal

|title=Enhancing Tumor-Specific Uptake of the Anticancer Drug Cisplatin with a Copper Chelator

|authors= Ishida, Seiko; McCormick, Frank; Smith-McCune, Karen; Hanahan, Douglas

|doi=10.1016/j.ccr.2010.04.011

|url=http://www.sciencedirect.com/science/article/pii/S1535610810001509

|date=15 June 2010

|volume=17

|issue= 6

|pages= 574–583

| journal =Cancer Cell}} {{Subscription or libraries|sentence|via=ScienceDirect}}

{{cite journal

|title=Neutron powder diffraction refinement of ilmenite-type bismuth oxides: ABiO3 (A = Na, Ag)

|authors=Kumada N.,Kinomura N.,Sleight A.W.

|doi=10.1016/S0025-5408(00)00453-0

|url=http://www.sciencedirect.com/science/article/pii/S0025540800004530

|date=November 2000

|volume=35

|issue=14-15

|year=2000

|pages=2397–2402

|issn=00255408

|journal=Materials Research Bulletin}}

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