In inorganic chemistry, why are phosphine ligands effectively used as spacers or protectors of metal centers?
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Because they effectively bind to but also dissociate from the metal center.  They protect the metal from reaction with undesired things until something which is a better ligand comes along and knocks it off.\nIt also serves to generate low-valent or even zero-valent forms of the metal (such as palladium tetrakis).
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It determines the number of ligands the ion can be surrounded with, both in the crystal and in solution. (Electronic configuration dictates the likely geometry.)\n\nThere is no direct correlation. Stability of the salt depends among other factors from the ionic character of the salt - some of the badly soluble sulfides have bonds with covalent character.\n\nThe energy gain from dissolving the salt (allowing free movement of formerly ordered crystals) has to be greater than the energy required to leave the crystal. Usually the ionic ligands in the salt crystal are replaced by water molecules.
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it is a measure of the number of chemical bonds formed by the atoms of a given element. it is used to explain the formulas of chemical compounds and to explain the elemental composition of a  specific element as it might occur in nature.
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Phosphoric Acid, H3PO4.
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That's an easy one... Ha Ha!\n\nA pi-acid is an acid that accepts electron density into it's pi-orbital.\n\nThe term, pi molecular orbital, is a symmetry designation.  A pi molecular orbital is antisymmetric with respect to a defining plane containing at least one atom (ie. the molecular plane of ethene).  A sigma molecular orbital is symmetric with respect to the same plane.  The terms are used both in this rigorous sense (for orbitals encompassing the entire molecule) and also for localized two-centre orbitals or bonds.  In the case of two-centre bonds, a pi bond has a nodal plane that includes the internuclear bond axis, whereas a sigma bond has no such nodal plane.\nInteraction between orbitals of different symmetries (with respect to the same defining plane) is forbidden!\n\n-- pi-acids or pi-bases usually apply to  Organometallic Chemistry and Molecular Orbital Theory.
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Charges on transition metals are determined based on the ligands, or other molecules, that are bonded to the transition metal.  Transition metals are considered to have 2+ charge in their solo state.  Since transition metals can have a variety of charges, they are very stable and versatile when it comes to ligand choice.
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go to inorganic industral chemistry book
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Work through them one-by-one. You need p or d orbitals that are oriented properly. The s orbital is symmetric, so it won't work for a pi bond. \nA. s orbital is the wrong symmetry for a pi-bond.\nB. py and dxy do appear to be oriented properly\nC, D, E - all have as one choice the px. Since the bond is along this axis, the px is not oriented properly for a pi bond. (The pi-bond has to have lobes that stick out to the side perpendicular to the axis of the bond).
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In chemistry, a metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds. Metals are sometimes described as a lattice of positive ions (cations) surrounded by a cloud of delocalized electrons. The metals are one of the three groups of elements as distinguished by their ionisation and bonding properties, along with the metalloids and nonmetals. On the periodic table, a diagonal line drawn from boron (B) to polonium (Po) separates the metals from the nonmetals. Elements on this line are metalloids, sometimes called semi-metals; elements to the lower left are metals; elements to the upper right are nonmetals.
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The monomers are linked by covalent chemical bonds.
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Sometimes they are useful to have a physical understanding of process, even if it is not entirely accurate.  Quantum chemistry is all approximations, however the predictions are sometimes very accurate and this can give us an idea of which molecular orbitals interact...and so on.\n\nSometimes reality is just to complex to have completely accurate models.
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most of the transition metals are used as catalyst\neg V,Fe,Ni,Pt,Pdetc\nthis is bcoz they have larger surface area and show variable oxidation state
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stable lutetium nuclides can be used as catalysts in cracking, alkylation, hydrogenation, and polymerization alloys.
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The metal should be absorbed by the ligand.  It's called chelation.  What about it?
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If you think of the radii of the orbitals as being rungs in a ladder, the rungs get closer together as you go up the ladder (get further away from the nucleus of the atom).  The reason why they get closer together is simply as there are more stable standing wave formations for electron orbitals the further you get away from the nucleus.\n\nThis is why the size of the atoms slow down in their increasing as you go down any group, not just the alkali metals.
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I assume you are talking about the formula and not the structure.\n\nThe molecular formula is C6H5NO5P\n\nStructure (if in case you want it too) is as follows:\n\nDraw a benzene ring (phenyl group) minus 1 hydrogen (C6H5). To the Carbon without the hydrogen, attach a Hydroxyl group (-OH). On the other Carbon positions, whether it is the ortho positions, meta positions, or para position, erase the hydrogen and attach a nitrate group (-NO2). On the Oxygen with the double bond to Nitrogen on the Nitrate group, erase one of the bonds and attach this bond to the phosphate group (-PO3).\n\nI'm not sure if you are talking about a nitro-phospho bond or a hydroxy-phosphate bond, but the difference is only 1 hydrogen.
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You should expect a molecular compound to form between N and O (as opposed to an ionic compound).  This is because N and O are both nonmetals.  An ionic compound will form when a metal and a nonmetal combine.  I believe that this is what your question is getting at.