Bismuth is a high-density, silvery, pink-tinged metal. Bismuth metal is brittle and so it is usually mixed with other metals to make it useful. Its alloys with tin or cadmium have low melting points and are used in fire detectors and extinguishers, electric fuses and solders. Bismuth oxide is used as a yellow pigment for cosmetics and paints, while bismuth(III) chloride oxide (BiClO) gives a pearly effect to cosmetics. Bismuth compounds have been widely used in medicine. After extensive use in the treatments of syphilis and other bacterial infections before the advent of modern antibiotics, bismuth compounds remain important for the treatment of several gastrointestinal disorders and also exhibit antimicrobial properties and cytotoxic activity, among others.

Cobalt is a lustrous, silvery-blue magnetic metal. Cobalt is a bioessential element due to its location at the centre of vitamin B12. Vitamin B12 plays a number of vital roles in the physiology of the human body. Cobalt is also important in treatments of radiotherapy in the form of the isotope 60Co. Other medical uses of cobalt include the detection of tumours and metastases, sterilisation of surgical equipment and the imaging of damage to the brain. Cobalt is also used in the prosthetic alloys sector, being utilised in hip, knee and dental replacements. There are inorganic cobalt complexes that elicit biological effects with potential use as pharmaceutical agents. Three classes of cobalt complexes are present: 1) complexes that directly act on biomolecules through ligand exchange, 2) complexes that modify the activity of ligated drugs and 3) complexes that are activated by bioreduction to either (I) yield a cobalt effector species or (II) release a small molecule drug. Cobalt can cause a distinctive, rapidly progressive and reversible depression of cardiac systolic function, which is readily distinguished from other causes of cardiomyopathy.

Cadmium is a chemical element with symbol Cd and atomic number 48. Its most common oxidation state is +2. Cadmium has no known biological function in higher organisms, but a cadmium-dependent carbonic anhydrase has been found in marine diatoms. In humans, the highest concentration of cadmium is absorbed by the kidneys and up to 30 mg of cadmium is commonly inhaled during childhood and adolescence. Cadmium is under preliminary research for its toxicity in humans, potentially contributing to risks of cancer, cardiovascular disease, and osteoporosis. The most risk of cadmium toxicity is from industrial exposure to inhalation of dust and fumes, or ingestion of soluble cadmium compounds.

Palladium is a rare and lustrous silvery-white metal. Palladium has the lowest melting point and is the least dense of platinum group metals. The primary use for palladium is in catalytic converters for the automotive industry. Palladium-based complexes are appealing alternative metal-based drugs because of significant similarities regarding structure and coordination chemistry with the platinum agents. Research suggests that one of the big reasons for the negative side effects of most anti-cancer drugs could be the use of the metal platinum as the core element in most of them. There is, however, evidence that the side-effects could be minimised by replacing it with a close metal relative, palladium. Currently, palladium complexes are being studied for their anti-cancer activity. Palladium nanoparticles (PdNPs) have attracted wide attention owing to their multifaceted utility in catalysis, sensors, and biomedical applications. Their therapeutic spectrum includes anticancer, antiviral, antibacterial, antifungal, antidiabetic, antioxidant potential which rationalizes the exploration of diverse physical, chemical, and biological routes for fabrication.

For a long time, platinum has been used in the design and manufacture of a range of medical implants and in clinically used platinum drugs with a central platinum(II) atom. After losing the respective leaving group and subsequent substitution with water, the positively charged molecules are nucleophilically targeted by the free electrons of the N7 atom of purines to form intrastrand and interstrand adducts. The established mechanisms of action of platinum drugs comprise platination of genomic and mitochondrial DNA. This leads to a hindrance of DNA-based functions (e.g., transcription, replication, etc.). Such cellular dysfunction eventually causes apoptosis, especially when DNA lesions cannot be repaired. Platinum-based anticancer drugs play a central role in cancer therapy. However, their applicability and efficacy are limited by drug resistance and adverse effects. Nanocarrier-based platinum drug delivery systems are promising alternatives to circumvent the disadvantages of bare platinum drugs.

IODINE I-123 is a radioactive isotope of iodine used in nuclear medicine imaging, including single photon emission computed tomography (SPECT) and X-ray computed tomography (X-Ray CT) scans. Iodine-123 is usually supplied as sodium iodide (NaI) and hypoiodite (OI−) in dilute sodium hydroxide solution, at high isotopic purity. 123I is the most suitable isotope of iodine for the diagnostic study of thyroid diseases. The half-life of approximately 13.13 h (hours) is ideal for the 24-h (hour) iodine uptake test and 123I has other advantages for diagnostic imaging thyroid tissue and thyroid cancer metastasis. The iodine is taken up by the thyroid gland and/or cancer metastasis and a gamma camera is used to functional images of the thyroid for diagnosis. Quantitative measurements of the thyroid can be performed to calculate the iodine uptake (absorption) for the diagnosis of hyperthyroidism and hypothyroidism. This is administered to a patient in capsule form, by intravenous injection, or in a drink.

Strontium is a soft, silver-yellow, alkaline-earth metal, existing either in the elemental state or as the divalent ion. Strontium occurs naturally in the earth's mantle as a mixture of four stable isotopes, i.e. Sr-84, Sr-86, Sr-87, and Sr-88. Of these, Sr-88 is the most prevalent form, comprising about 83% of natural strontium. Natural stable strontium is abundant in the environment and can be found in all plant species. Consuming 75% of production, the primary use for strontium is in glass for color television cathode ray tubes, where it prevents X-ray emission. Acantharea, a relatively large group of marine radiolarian protozoa, produce intricate mineral skeletons composed of strontium sulfate. In biological systems, calcium is substituted in a small extent by strontium. In the human body, most of the absorbed strontium is deposited in the bones. The ratio of strontium to calcium in human bones is between 1:1000 and 1:2000, roughly in the same range as in the blood serum. The human body absorbs strontium as if it were its lighter congener calcium. Because the elements are chemically very similar, stable strontium isotopes do not pose a significant health threat. The average human has an intake of about two milligrams of strontium a day.

Phosphorus P-32 (P-32) is the phosphorus isotope whose nucleus consists of 15 protons and 17 neutrons. Phosphorus P-32 is one of the most commonly used research emitters and is the one with the highest energy. Its use in molecular biology has become widespread by the use of specific high-activity nucleotides to mark DNA. Phosphorus P-32 may also be used in phosphorylation reactions. More precisely, it is used in the study of the migration of fertilizers (phosphates) in soils. In the medical field, phosphorus P-32 has been used for the treatment of polyglobulia, but this is increasingly rare. Emitted by phosphorus P-32, beta particles directly damage cellular DNA and, by ionizing intracellular water to produce several types of cytotoxic free radicals and superoxides, indirectly damage intracellular biological macromolecules, resulting in tumor cell death.