what is a crystal shape and a high melting point?
454982
A crystal shape is the arrangement of the molecules in a compound...carbon fiber is a crystalline structure since it is arranged in a pattern when observed under a microscope. Glass, however isn't a crystalline structure, and will be disorganized. Also, a quick fact is that glass will always be in motion due to it's non-crystalline structure. The bottom of a pane of glass will be thicker than the top after many years :) A high melting point means that it will take more heat to induce a state change... Metal is frozen at room temperature and has a high melting point, as opposed to water, which has a melting point around 33 degrees farenheit.
1111193
In my years of teaching, it seems that everything in chemistry is related to stability.  The network solids are very stable structures and form strong bonds.  \n\nA melting point in chemical terms is when the physical property of heat is capable of changing the configuration of the bonds.  This configuration will be resistant to change if it is in a stable state, because the change to the liquid form is an increase in entropy (chaos).  Therefore a high temperature would be required to change the form.
731753
NDA? DNA? Because X-ray crystalography showed it to be that shape. Read Nature vol 171 pg 964
38819
Transition metal.\n\nName: Copper \nSymbol: Cu \nAtomic Number: 29 \nAtomic Mass: 63.546 amu \nMelting Point: 1083.0 °C (1356.15 K, 1981.4 °F) \nBoiling Point: 2567.0 °C (2840.15 K, 4652.6 °F) \nNumber of Protons/Electrons: 29 \nNumber of Neutrons: 35 \nClassification: Transition Metal \nCrystal Structure: Cubic \nDensity @ 293 K: 8.96 g/cm3 \nColor: red/orange
809561
malleable and ductile lustrous conduct heat and electricity high melting points almost all are solids at room temp except mercury
697102
The main constituent of Flat Glass is SiO2 (silica sand). This has a high melting temperature in the region of 1700 degrees C and its state at this temperature is like syrup on a very cold day.\nFor practical and economic reasons, the high melting point and viscosity of silica is reduced by adding sodium oxide (a flux)
971812
In crystalline matter everything is oriented in an identical repeating matter.  For example, an auditorium where everyone is regularly spaced and all facing the same way can be thought of as a "2d crystal."  In amorphous structure everything is irregularly oriented and does not have regular spacings.  Crystalline materials have very well defined properties (melting points, optical properties, diffraction), and amorphous materials do not (no distinct melting points, more complicated optical properties, etc.).\n\nWith specific regards to durgs or polymers, most polymers form amorphous materials.  Drugs, being smaller and well-defined molecules, can be crystallized much more easily, although they are not necessarily crstalline.  However, crystals are useful for determining structures, and usually correlate very well with high purity, which is very desirable with medicines.
148297
The melting point of diamond is the highest of all known natural substances, over 3800 K, which converts to 6,380 degrees Fahrenheit.  (Carbon's tetrahedral network solid structure is responsible for the high melting point.)  \nAlthough the diamonds themselves did not melt, the earrings' metal may have melted, depending on what it was.  In any case, your earrings are small and would be difficult to locate in the ruins of a burned down house.  If they haven't been stolen, they're definitely still there.
55435
jtkeel is mostly right, except the structure of copper is not crystaline.  Al3K is right about the structure of copper, which is the basic structure of all metals and is what gives them their physical characteristics, like their malleability, conductivity and so forth.
889851
Your unknown compound might be an impure substance.  The impurities will skew the melting point.  You should find out if the substance is pure or not.  Pure substances (that is, with nothing else mixed with them) will have a narrow ranging in which they melt, for example, pure Naphthalene melts between 83-85 Celsius.
914315
Andalusite is a polymorph with two other minerals; kyanite and sillimanite. A polymorph is a mineral that shares the same chemistry but a different crystal structure with another, or other, minerals. A unique variety of andalusite is called "chiastolite". It contains black or brown clay and/or carbonaceous material inclusioned in the crystal. These inclusions are arranged in regular symmetrical shapes. Usually they are in the form of a cross or X. \n\nPHYSICAL CHARACTERISTICS:\nColor is white, red, brown, orange and green. \nLuster is vitreous. \nTransparency crystals are transparent to translucent. \nCrystal System is Orthorhombic; 2/m2/m2/m \nCrystal Habits include prismatic crystals with a square cross section terminated by a pinacoid. also massive and granular. \nCleavage is good in two directions. \nFracture is splintery to subconchoidal. \nHardness is 7.5 \nSpecific Gravity is approximately 3.15+ (above average) \nStreak is white. \nAssociated Minerals are cordierite, biotite, feldspars, quartz, kyanite and sillimanite. \nOther Characteristics: dark inclusions produce cruciform shapes in the variety, chiastolite. Index of refraction is 1.632-1.638. \nNotable Occurrences include Andalusia, Spain; Austria; California, USA and China. \nBest Field Indicators are crystal habit, color, inclusions (if present) and hardness.
729392
There is a strong ionic bond between Ag+ and I- ions thanks to electrostatic attraction. This attractions makes the solid very solid (sable). That is why the melting point is rather high.\nThe attraction between the molecules of vanillin is much weaker, so this molecules can be separated by melting much easier. (This has been called quadrupole or octupole attraction, better known as vanderwaals force (cohesion)).\n\nTh
388144
That's a trick question; the lattice parameter changes as the crystal passes through an "order-disorder transition", but only by around 0.04%.\n\nThe nearest neighbour distance is 2.531 Angstroms, which corresponds to a lattice parameter of 3.580 (I believe) for this type of lattice (Cu3Au, which is essentially face-centered cubic).
867788
Liquid.  Melting point is 600.65K
787518
What the first reply means is that since it is ionic, it does not have a molecular shape.  It is NOT a molecule.  The Zn+2 ion and the Br- ions will form crystals.  They have a unit formula of ZnBr2 (not znbr2) but it is not a molecule.
400116
Crystal Silimanite\n \nMolecular Weight (g/mol.) 162.04558 \nApparent Density (g/cm3) 3.24 \nBulk Density (g/cm3) 3.24 \nMelting Point (°F) 3290 \nBoiling Point (°C)   \nSurface Area (m2/g)   \nThermal Conductivity (cal/s-cm-°C)   \nMohs Hardness @20°C 6 - 7 \nSpecific Gravity (g/cc) 3.2 \nParticle Shape   \nScreen Analysis   \nCrystallography orthorhombic \n\n\n\nFrom what i am reading they are the same
122405
erm, high, like really hot. ok, the melting point of α-D-glucose: 146°C\nβ-D-glucose: 150°C [1]\nit probably decomposes before it boils but i found this phase change data [2]\n\nQuantity Value Units Method Reference Comment \nTfus 423. K N/A Kofler and Sitte, 1950 Uncertainty assigned by TRC = 3. K; With "hot stage" \nTfus 420. K N/A Kofler and Sitte, 1950 Uncertainty assigned by TRC = 4. K; By "differntial thermal absorption" \nTfus 414. K N/A Parks and Thomas, 1934 Uncertainty assigned by TRC = 2. K