FCC and HCP 5 Best difference You should Know

An Introduction to FCC and HCP

FCC (face-centered cubic) and HCP (hexagonal close-packed) crystal structures can often be found in alloys and metals. Within FCC structures, atoms are organized in an arrangement similar to cubic shapes with additional atoms at either edge.

HCP crystal structures consist of hexagonal close packing of the same size cube. HCP structures feature compact geometry with high symmetry; every six-atom unit forms hexagonal patterns arranged around its center axis.

HCP structures contain tighter packing of atoms than FCC structures, leading to greater density. Each crystal structure can lead to different physical properties that influence its application – FCC materials tend to be more ductile while those made using HCP structures tend to be stronger and less susceptible to deformation.

 Importance of understanding the differences between FCC and HCP

Knowledge of FCC and HCP crystal structures is vitally important, for many reasons:

1. Material Selection: The crystal structure of any material has an enormous effect on its thermal, mechanical, and electrical characteristics. By understanding FCC versus HCP materials scientists and engineers can select an ideal material for each specific task at hand.

2. Manufacturing Processes: The crystal structure of materials may have an influence on their manufacturing. For instance, HCP materials tend to be harder to process and machine than FCC ones.

3. Analyzing microstructural structures: Substance structures can be identified using various microstructural analysis techniques such as X-ray diffracted diffraction and electron microscopy. By understanding the distinctions between FCC structures and HCP ones, scientists are better equipped to interpret and analyze microstructural information more efficiently.

4. Research Foundation: Examining FCC and HCP structures are central components of materials science and condensed matter Physics research. Their properties and behaviors often depend on their crystal structures; understanding these structures could assist researchers in creating innovative materials and techniques.

What is FCC?

FCC (face-centered closed packing cubic structure), comprising lattices, is an efficient space mixture crystal structure. It has an estimated coordination number of 12 with four atoms being in contact within each cell – which accounts for 74% of space occupied – leaving only 26% unfilled! This structure takes up 74% of the available area; only 26 percent remains vacant!


FCC (face-centered cell) structures consist of unit cells that have one atom located centrally on one face of their cells – this structure type can also be known as face-centered. FCC layers in cubic close-packed arrangements feature three circulars, repeating layers; with differing planes between layers. Metals such as aluminum copper gold silver lead contain this form.

What is HCP?

HCP (Hexagonal Close Packing Structure of Lattices) is an efficient space-saving crystal structure. With only six atoms per cell and its coordination number at 2, HCP takes up 74% of space with only 26% left for empty space (in this example). HCP layers rotate between two levels while their third layer mirrors their first.


Cobalt, Cadmium zinc and titanium all possess Hexagonal crystal structures with close packed hexagonal crystal structures cobalt also has close packed Hexagonal crystal structures similar to this type of Arrangement.

Difference Between FCC and HCP


Crystal Structures

A Crystal structure is defined as any three-dimensional Arrangement of atoms or molecules inside of a solid crystal material that defines several chemical and physical properties Associated with that substance including strength density and Conductivity. FCC and HCP crystal structures are two common examples found among alloys and metals respectively.

FCC structures involve the arrangement of atoms into a cube-like lattice with additional atoms added at random across each face to form an tightly packed structure with high symmetry and low energy consumption.

Each atom within this arrangement is enclosed by 12 of its closest neighbors – making the FCC structure highly symmetric and low energy consumption. It’s distinguished by a coordination number 12 signifying this is indeed an FCC structure.

HCP structures consist of hexagonally packed hexagonal lattices arranged such that each layer sits directly atop of its predecessor layer, producing an extremely symmetrical arrangement with strong directionally bonding properties and being easily distinguished by their coordination number of 12. An HCP is further identified with 12 as its coordination number.

Other alloys and metals exhibiting different crystal structures include BCC (body-centered cubic) and diamond cubic structures, both known to significantly influence mechanical, thermal and electrical properties of metals; as such they play a pivotal role in choosing materials for design purposes as well as selection processes.

Examples of FCC and HCP materials

Examples of materials with FCC crystal structure include:

  1. Aluminum
  2. Copper
  3. Gold
  4. Silver
  5. Nickel
  6. Platinum
  7. Lead
  8. Iron
  9. Palladium
  10. Cobalt

Examples of materials with HCP crystal structure include:

  1. Magnesium
  2. Titanium
  3. Zinc
  4. Cadmium
  5. Beryllium
  6. Zirconium
  7. Hafnium
  8. Ruthenium
  9. Osmium
  10. Lutetium

It’s worth noting that not all materials with a given crystal structure exhibit the same properties, as the properties of a material also depend on its chemical composition, defects, and processing history.

Stacking Sequence

In terms of crystal structures, stacking sequence refers to the arrangement of atoms and ions within each layer of its lattice structure. It plays an integral part in shaping properties associated with materials; its effects could include changing symmetry as well as density or even mechanical strength of crystal structures.

An FCC structure’s stacking sequence could be described as ABCABC…, in which each layer possesses atoms arranged according to an ABC pattern. This creates an extremely compact structure with great symmetry.

An HCP structure’s stacking sequence could be described by using the term ABABAB…, where each layer consists of atoms arranged according to an AB pattern and creates an hexagonal closed-packed structure with strong bonds in all directions.

Different crystal structures contain distinct stacking patterns. For instance, BCC (body-centered cubic) structure contains layers with an ABC pattern similar to FCC structure but with slight modifications. Each layer consists of atoms arranged according to this ABC sequence with slight variance from FCC.

Cryostat stacking patterns can be measured experimentally using techniques such as electron microscopy or X-ray diffraction and provide important insight into material properties and behaviour.

Physical Properties

A material’s physical properties define its behavior under various physical conditions like temperature and pressure fluctuations as well as electromagnetic fields. A material’s physical characteristics may also depend on factors like its structure chemical composition defect types as well as processing history.

Some physical properties affected by crystal structure include:

1. Density: A substance’s density can be determined by both dimensions and arrangements of molecules or atoms within its crystal structure, with materials having FCC structures tending to have greater densities compared with HCP structures.

2. Mechanical Properties: Mechanical properties can be determined by its crystal structure; materials that feature FCC structures tend to be more flexible and ductile than HCP structures.

3. Thermal Properties: The crystal structure can have an influence over thermal properties in materials, including their thermal conductivity and energy density, such as thermal conductivity or energy density.

4. Electrical Properties: Electrical properties ascribed to substances can vary significantly based on factors like their structure or the presence of defects; resistance and conductivity of materials in particular being affected in this regard.

5. Optic Properties: When it comes to materials’ optical properties – like its refractive index or absorption spectrum – their refractive index and absorption spectrum can be determined based on both crystal shape and how molecules or atoms arrange themselves within.

Understanding the relationship between crystal physical and structural properties is vital in selecting materials and designs for various applications including aerospace engineering, electronics manufacturing and biomedical engineering.


Crystal Structure of Different Materials For instance: Here are several applications where crystal structures could prove helpful:

1. Electronics: Many FCC crystal formed metals and alloys such as aluminum and copper have found widespread application in electronics due to their excellent conductivity of electricity and ductility properties.

2. Structural Materials: Materials such as titanium alloys and steel with BCC or FCC crystal structures are frequently employed for structural applications due to their durability, strength, and adaptability.

3. Aerospace: Materials with hexagonally close-packed (HCP) crystal structures such as titanium alloys and magnesium are widely utilized for aerospace applications due to their superior strength-to-weight ratio and corrosion-resistance capabilities.

4. Medical Implants: Certain biocompatible materials like titanium and its alloys such as HCP crystal form have proven suitable for use as dental and orthopedic implants, making these materials widely utilized by medicine for such implants as dental crowns or knee prostheses.

5. Jewelry: Production Precious metals like silver and gold that possess FCC crystals are often utilized for jewelry manufacturing due to their attractive aesthetic and superior formability properties.

6. Catalysis: Catalysts composed of substances with specific crystal structures such as HCP zeolites can serve as catalysts in chemical reactions due to their large surface area and selective adsorptive capabilities, making for efficient reactions with many substances.

Understanding the physical and crystal structures of materials is integral in assessing their potential uses as well as designing new ones that match specific requirements.


Crystal structure plays a vital role in defining both chemical and physical properties of materials as well as potential applications of these. There are two types of crystal structures present: FCC crystal structures are predominant among many metals and alloys while HCP structures tend to occur less commonly.

They possess unique stacking sequences and various arrangements of particles or ions.

Understanding the differences between FCC and HCP structures is integral for selecting materials with specific properties for various applications in aerospace, electronics, biomedical engineering and catalysis applications.

Recent advances in engineering and materials science continue to expand our knowledge about crystals – pushing beyond what was thought possible with regard to new and exciting materials that can serve a multitude of uses.